Timeline: 4th Century (Gaul Rising)

Building Relations With Arab Tribes
The Osrinian War had cost Rome an important ally, Armenia. Persia had forced Armenia to agree to be neutral in all Perso-Roman conflicts. The war had also secured the independence of Osroene, a former Roman province and an ally of Persia. Meanwhile, the Arab kingdom of Lakhm was steadily expanding and beginning to exert influence beyond its borders. These things left Rome diplomatically isolated and with an enemy right at its border in the Middle East.

Starting in 301, Roman Emperor Messalla began a project to build trade and diplomatic relations with tribes in northern Arabia. His hope was to eventually gain at least one ally for Rome to counterbalance Osroene.

Reconquest of Cappadocia
Since 298, Messalla had been taking steps to rapidly rebuild the Roman army so that he could launch an invasion of the breakaway province of Cappadocia. These efforts were a success: between 298 and 304, approximately 30,000 men enlisted. In 304, Messalla, Maximian, and several prominent generals agreed that the time was right to invade Cappadocia.

The invasion began in May 304, with 40,000 Roman soldiers participating. Messalla opted for a two-front invasion. 25,000 of the participating men would invade from the southwest, and the remaining 15,000 would stage a naval invasion from the north. Both groups were able to break through the Cappadocian defenses. After winning the initial battles, the Romans steadily gained territory. In October, the governor of Cappadocia surrendered and recognized Messalla's authority.

After Rome retook Cappadocia, the northern part of the province was given to the province of Pontus, and the eastern half was made into a separate province called Armenia Minor. The provinces were added to the Dominium Caesaris. The governor of Cappadocia and most of his important civil and military officials were allowed to retire.

Gallic Reaction
Word of the Roman reconquest of Cappadocia did not reach Colonia Agrippina until a year after the fact. By 302, Tetricus and the Gallic Senate did know that Messalla was rapidly rebuilding the Roman army. Tetricus and the Senate agreed that the appropriate response was to take steps to expand the Gallic army.

The Assassination of Tetricus
Upon being elected First Citizen of Gaul, Tetricus had designated Carausius as his successor, but only to win the support of senators who would have otherwise supported Carausius. Throughout his reign, Tetricus consistently marginalized not only Carausius but also his closest associates, and reserved important civil and military offices for Postumians. The purpose was to make it so that if Carausius did indeed succeed Tetricus, he would lack meaningful leadership experience, and be heavily dependent on Postumians who had been groomed to exercise the real power.

By 304, Carausius had decided that the only way he could ever hope to rule without being a puppet of allies of Tetricus was by having Tetricus assassinated and seizing the throne by force. Now at this time, Carausius was governor of the province of Asturia (in northern Spain). On March 9, he sent a letter to a longtime friend of his named Sextus Aurelius Allectus. At that time, Allectus held a minor military command in Belgica (specifically, he was a centurion), so he was the closest person to Colonia Agrippina whom Carausius trusted. In the letter, Carausius promised that if Allectus were to participate in the assassination, he would be rewarded with an important role in the government under Carausius, and possibly even be chosen to succeed Carausius; assurred Allectus that if he declined to participate, it would not be held against him; and asked Allectus to tell him whether or not he was willing to oversee the assassination. Allectus received the letter on April 27; and on May 2, Allectus sent a reply in which he informed Carausius that he was willing to participate.

Planning the assassination was Allectus' responsibility, since he was much closer to Colonia Agrippina than Carausius. He had several friends and associates in Colonia Agrippina. Without revealing his intent to have the emperor murdered, he began asking those contacts about the people they knew and regularly dealt with. Specifically, he asked if any of them knew men who could be considered highly unscrupulous or men who were desperate to escape debt or poverty. He also sent a couple of men under his command to visit nearby prisons to learn about the people who being held there. He also noting which of the men in his unit stood out as particularly ambitious. Allectus' goal was to find several people who easily could be bribed into participating in the assassination.

Over the summer of 304, the details of the plan began to take shape. Several men would be trained in archery. Once Allectus was satisfied that their skills as archers were good enough, a date for the assassination would be selected. On that date, the assassins would hide near the building where the Senate met, and shoot as he was about to enter. Thereafter, the assassins would be hidden. Once Carausius had secured his authority over the Gallic Empire, the assassins would received whatever rewards they were promised.

At the same time that the plan was developing, however, the activities of Allectus aroused the suspicions of his immediate superior, the commander of the cohort that Allectus' unit was a part of. He noticed that men under Allectus' command would sometimes be absent. Also, the volume of mail to and from Allectus began to increase. At the same time, jailers in Belgica were beginning to wonder why Roman soldiers were wanting to learn everything they could about the current prisoners, as well as prisoners who had been released. In spite of this, there was nothing to clearly suggest that Allectus was involved in any conspiracy. Allectus had considered bribing the guards to release one or two prisoners, but he eventually chose not to do that, feeling that that would implicate him in the killing of the emperor.

On July 6, Carausius received Allectus' letter in which Allectus informed Carausius that he was willing to oversee the assassination of the emperor. After Carausius received and read the letter, he immediately began preparing to leave Lucus Asturum (OTL Llanera) for Colonia Agrippina, and he left on July 20.

The assassination of Tetricus took place on the morning of September 8, 304. On that day, Tetricus was on his way to the Senate building. Five men were hiding at different points near the entrance. Two were criminals who had previously served time in prison, one was a farmer who was deeply in debt, and two were low-ranking but ambitious soldiers in Allectus' unit. As Tetricus began to walk up the steps that led to the door, all five of the assassins shot arrows at him. Each assassin had dipped his arrows in poison. Three of the arrows hit Tetricus, and he fell to the ground. Each of the assassins shot a second arrow; and one of those arrows hit him, and three hit his bodyguards. Thereafter, all five of the assassins fled the scene. Tetricus and the two bodyguards of his who were shot died within minutes.

The First Gallic Civil War
Main article: First Gallic Civil War

Carausius arrived in Colonia Agrippina on September 18, 304 and immediately assumed the throne. Immediately, suspicion arose that Carausius was involved in the assassination of Tetricus. Also, the Postumians anticipated that Carausius would either purge them from the Senate and the military or create new Senate seats for his partisans to dilute their influence. The Postumians secured an agreement from Carausius to not alter the membership of the Senate for six months. They used this time to investigate the assassination of Tetricus and garner votes to depose Carausius.

By February 305, the Postumians had uncovered evidence that Carausius had orchestrated the killing of Tetricus. Also by this time, Carausius had had several senators assassinated and bribed and intimidated several others into doing his bidding. The Postumians knew it was time to act. They persuaded the most senior senator to call a meeting on February 16 after dark for the purpose of deposing Carausius without giving the Princepist faction any advance notice. To justify holding the vote, the senior senator adopted an interpretation of the rules of proceedings that essentially gutted them. Seventy-five senators walked out of the meeting just before the vote was held. The remaining senators voted to depose Carausius. The Senate appointed Aurelius Arpagius, a general who had fought in the Amasigan War and the governor of the province of Massiliensis, as the new First Citizen; and the Senate also declared that Tetricus' son, known as Tetricus the Younger, would become First Citizen in the event of Arpagius' death.

Carausius refused to recognize the Senate's vote to replace him, and he declared the senators who had voted to depose him to be expelled from the Senate. Likewise, the senior senator refused to recognize the dismissals made by Carausius. The Senate itself split into two bodies: one consisting of the senators who had voted to depose Carausius, and the other composed of the senators who had either walked out of the overnight meeting or voted against deposing him. For several days, the situation in Colonia Agrippina was tense but nonviolent; but on February 24, 305, Carausius sent troops loyal to him to arrest the pro-Arpagius Senate. Most of the pro-Arpagius senators avoided capture; but by February 26, they were forced to flee Colonia Agrippina. This marked the beginning of the First Gallic Civil War.

During March 305, military commanders and civil officials chose sides as word of the events of late February spread throughout the empire. The pro-Arpagius Senate moved to Augusta Treverorum (OTL Trier), while Carausius and his Senate relocated to Turnacum (OTL Tournai). Arpagius and Tetricus the Younger learned about the Senate vote and the outbreak of the war in late March. By April, most of northern and western Gaul, a few areas in Spain, and the province of Britannia Superior had sided with Carausius; while the rest of the empire had accepted Arpagius.

During April, Arpagius prepared for a campaign to retake Colonia Agrippina and Tetricus the Younger planned a campaign to seize a strip of land running right through the middle of Carausius' core territory, while Carausius planned an effort to take Augusta Treverorum. Meanwhile, supporters of Arpagius in Spain took the initiative of beginning a campaign to take over the areas loyal to Carausius. Both Carausius and Tetricus the Younger began their campaigns in late April.

The forces that Carausius sent to take Augusta Treverorum failed. By the middle of May, Arpagius had learned about the presence of the forces attempting to take the city, and he and the legions that were with him intercepted them. The pro-Carausius units were wiped out. Then in June, Arpagius led several legions to take Colonia Agrippina and the surrounding areas. He hoped that taking the empire's capital would lead to the death or arrest of Carausius and the end of the war. He only learned after taking over Colonia Agrippina that Carausius had long since left. Several weeks after the Second Battle of Colonia Agrippina, Arpagius sent troops to advance westward. These forces were able to gain control of an area that almost extended to the Mosa River (OTL Meuse).

Tetricus the Younger spent the summer of 305 trying to take over a strip of land running through the middle of northern Gaul. The purpose of this campaign was to cut Carausius off from half of his territory. Tetricus the Younger did gradually advance through northern Gaul, but his forces were repeatedly intercepted by forces loyal to Carausius.

The British theatre of the war began in June 305, when the governor of Britannia Inferior, Flavius Dannicus, and the dux of Britain, Julius Proculus, agreed to take the initiative of invading Britannia Superior. Dannicus and Proculus both supported Arpagius; and their goal was to remove the governor of Britannia Superior, named Lucius Durus, and then send troops to aid Arpagius and Tetricus the Younger in Gaul. The effort to take Britannia Superior culminated in the Battle of Londinium and the Battle of Noviomagus Reginorum, both of which took place in August, and which resulted in the complete takeover of Britannia Superior by Proculus.

In October, Proculus sent several legions to invade the areas in Gaul that Carausius controlled. This led to the end of the war. With the help of the Britannia forces, Tetricus the Younger was able to finish carving a swathe through Carausius' territory, and then win several other cities. Several senators and generals who had supported Carausius became disillusioned with him; and on November 8, they arrested him and ordered all the military units who had sided with Carausius to surrender and recognize Arpagius as First Citizen. Not all of Carausius' supporters obeyed these orders, so the war did not end until January 5, 306.

305 and 306
In September 305, Messalla decided to exploit the fact that the Gallic Empire was in a state of civil war. Rather than attack the Gallic Empire itself, Messalla decided to invade Gaul's allies, the four Germanic states in Pannonia and Noricum. The Roman invasion of Pannonia and Noricum began on September 22, 305. Messalla sent a large invasion force to the area, and the Pannonian and Norican states were caught off-guard. Because of this, the Romans were able to conquer all of Suevia by October 18 and a third of Marcomannia by the end of October. During October, the governments of all four countries sent letters to Arpagius requesting aid.

Arpagius learned about the invasion of Pannonia and Noricum by late November 305. By this time, he had learned about the downfall of Carusius, so he believed that he could afford to aid the Germanic states. Arpagius promptly sent two legions and four auxiliary units to assist the Pannonian and Norican armies. He also sent troops to invade the Roman Empire itself. Meanwhile, the governor of Raetia took the initiative of sending three auxiliary units into Alamannia (but only Alamannia).

The Gallic units that were deployed to Pannonia and Noricum arrived in January 306. By that time, the Romans had taken two thirds of Marcomannia and almost half of Quadium. Alamannia, on the other hand, had remained mostly unconquered, thanks in part to the help from the Gallic units that had already been sent there.

At the same time that Gallic troops were entering Pannonia and Noricum, four legions and eight auxiliary units set sail from southern Gaul to invade the Roman provinces of Numidia, Mauritania Caesariensis, and Mauritania Sitifiensis; and another two legions and four auxiliary units sailed to Corsica. In February 306, two legions and six auxiliary units from Spain received and carried out orders to invade Mauritania Tingitana. Meanwhile, two additional legions were sent to defend Gaul's already heavily protected border with Italy. Altogether, Arpagius had chosen to invest almost half of the Gallic Empire's total military strength in the war with Rome.

Arpagius' strategy paid off. The presence of the Gallic forces in Pannonia and Noricum enabled the local armies to hold the line against the Romans and even retake a few areas, which bought time for the invasion of Corsica and the west African provinces to proceed. In the Roman provinces that the Gallic Empire invaded, the Gallic forces outnumbered the Roman forces; and in Corsica and Numidia, the local Roman forces were caught completely by surprise.

The general purpose of the invasion of the Roman Empire was to force Messalla to withdraw the troops he had sent to Pannonia and Noricum. Arpagius also intended to permanently annex Mauritania Tingitana and at least temporarily occupy Corsica. The forces sent to Numidia, Mauritania Caesariensis, and Mauritania Sitifiensis were ordered to plunder and destroy as many cities and towns as possible within a month, and then leave.

Messalla learned about the invasion of Corsica first, and he responded by sending troops that were stationed in Italy. After he received word about the invasion of the African provinces, he sent two legions from Italy to northwest Africa. To partially compensate for the absence of troops in Italy, he pulled one legion from Noricum and two auxiliary units from Dalmatia.

By the time the Italian legions arrived in Africa, most of the Gallic forces were already gone. Per orders from Arpagius, one legion and three auxiliary units moved to Mauritania Tingitana to help with the invasion of that province, one legion and the other five auxiliary units sailed to Corsica to bolster the Gallic presence there, and the other two legions retreated to southern Gaul and western Spain. After this, the Romans attempted to retake Mauritania Tingitana and Corsica, but they were repeatedly repelled. In Noricum and Pannonia, help from the Gallic troops had enabled the Germanic states to steadily win back territory from the Roman Empire. Also, the departure of an entire Roman legion made it possible for resistance cells to form in the areas that were occupied. By May, the resistance movement had taken control of several small towns and two relatively large cities. Most of the Roman troops were near the front lines at this point, but the legion commanders were forced to move some cohorts to the interior to deal with the rebellion. The tactics used by troops sent to quell the rebellion only outraged the people and prompted more people to join the uprising. By July, it was clear to the generals commanding the invasion force that they could not fight both the armies of Gaul and the Germanic countries and the resistance cells over an area as wide as the entire Noricum-Pannoia region, so they ordered their forces to retreat to the area south of the Dravus (OTL Drava) River. Even then, Gallic and Germanic forces were still able to chip away at the Roman gains, so the Roman generals soon ordered a retreat to the area south of the Savus (OTL Sava) River.

In late August, Maximian sent one legion under his authority to the Noricum-Pannonia front, another to Corsica, and a third to Mauritana Tingitana. The legion bound for Pannonia and Noricum arrived on October 1, 306. During October and November, the Romans were able to steadily regain territory. The legion that was sent to the Corsica front arrived on October 17. This legion was less successful: not only did the Gallic army still have a large military presence there, but it had also bolstered its strength by bribing hundreds of local Roman soldiers into defecting to the Gallic Empire. News of the arrival Roman of additional Roman forces in Pannonia and Noricum reached Gallic territory by late October. On November 3, the dux of one of the Gallic Empire's eastern military districts took the initiative of sending a legion to the area. This legion arrived on November 26. The Gallic and Germanic armies won several victories during the first half of December, but then a stalemate developed. Meanwhile, the legion sent from the Dominium Caesaris to Mauritania Tingitana arrived on December 4. That legion's presence there did not help the Romans: the Gallic presence was simply too strong.

307
On January 4, 307, Messalla ordered a complete withdrawal of Roman troops from the area north of the Savus River. The legion from the Dominium Caesaris was to return there, while the other two legions were to hold the line at the Savus. Messalla also ordered one of the two legions he had sent to Africa to go to Corsica to retake the island. The Roman legion that was redeployed to the Corsica front arrived at northern Sardinia on January 26. On February 8, it and three other legions staged a massive attack on Corsica. The Gallic forces won, but their victory was costly. On February 14, the general who had been acting as governor of Corsica sent a letter to Arpagius asking him to allow a full retreat from Corsica. After another pyrrhic victory against Roman forces on March 1, the governor of Corsica decided to abandon Corsica without waiting for Messalla's approval. By the time the invasion force pulled out of Corsica, over a quarter of its participants had died.

After the Gallic withdrawal from Corsica, half the invasion force went to Mauritania Tingitana, and the other half went to Gaul's pre-war territories. For several months after this, the Romans repeatedly made failed attempts to retake Mauritania Tingitana, while the Gallic and Germanic armies failed to take anything south of the Savus. Finally, on June 15, 307, Messalla sent a letter to Arpagius to offer terms for an armistice: Messalla was willing to accept the loss of Mauritania Tingitana, provided Arpagius were to accept Roman control over the parts of Pannonia and Noricum south of the Savus. While awaiting a reply from Arpagius, Messalla ordered his forces to hold the line at the Savus and the border of Mauritana Tingitana, but not attempt to move beyond those boundaries. This effectively marked the end of the war. On September 4, Messalla received a letter from Arpagius in which Arpagius stated that he accepted Messalla's terms.

The African Rebellion
For several years before the Third Gallo-Roman War, discontent with Messalla had started to appear in the African provinces. The people of the African provinces (especially Numidia and the Mauritanian provinces) were beginning to believe that Messalla had neglected them relative to the rest of the empire. After the war with Gaul, the dissatisfaction with Messalla grew rapidly in northwest Africa.

By March 308, riots targeting local Roman officials were happening in many cities in northwest Africa, and militias were beginning to form. During June 308, militias seized control of three cities in Mauritania Caesariensis and one city in Numidia. Some army units joined up with the militias, while others tried to crush the rebellion. On June 13, 308, Gaius Annius Anullinus, the governor of Numidia, declared himself Supreme Senator (senior co-emperor) and his son Caesar (junior co-emperor). After this, several legions quickly turned against Messalla.

Anullinus promptly sent two legions and three auxiliary units to invade Rome. These legions left Africa on June 28 and arrived in central Italy on July 10. The invasion of Rome took place on July 13. There was only one legion protecting the city, and with that legion outnumbered and caught off-guard, the city quickly fell to Anullinus' forces. Messalla managed to escape to Spoletum (OTL Spoleto). From there, he summoned troops to Italy, informed Maximian of his situation, and ordered generals loyal to him in Africa to invade Numidia. The invasion of Numidia began on August 12. On August 16, Messalla led a campaign to retake Rome. By August 17, Anullinus' forces had been driven out of Rome, and pro-Messalla forces were closing in on Cirta (OTL Constantine), the capital of Numidia. On August 20, a legion in Mauritania Sitifensis that had remained loyal to Messalla seized control of Sitifis (OTL Sétif), the provincial capital. By then, most of the pro-Anullinus forces in Numidia had capitulated. On August 21, pro-Messalla forces took Cirta and killed both Anullinus and his son.

Messalla was injured in the battle to retake Rome from Anullinus. The wound was treated, but it became infected. Messalla died from the infection on August 24, 308. The local officials quickly sent the news of Messalla's death to Maximian, who was in Thessalonica. Maximian received the news on October 10. Maximian's first act as Supreme Senator was to make his son Maxentius the new Caesar of the Dominium Caesaris. Maximian left Thessalonica for Rome on October 31, and he arrived on December 17.

Consolidating Power
Arpagius learned about the coup against Carausius on November 18, 305. On November 27, he ordered Carausius to be transported to Colonia Agrippina. Carausius arrived on December 27. On January 20, 306, Carausius was put on trial for orchestrating the murder of Tetricus the Elder and leading a rebellion against Arpagius. The trial ended on January 24. Carausius was found guilty and sentenced to death, and this sentence was carried out on January 30.

Arpagius pardoned the senators and generals who had led the coup against Carausius, and he allowed them to keep their respective Senate seats and military commands. The remaining pro-Carausius senators were expelled from the Senate and put on trial for aiding the rebellion, and all but nine of them were convicted; and those convicted received sentences ranging from ten years in prison to death. Arpagius' treatment of generals and other high-ranking military officers who had supported Carausius was mixed. Some of the ones who had not actually engaged in combat against forces loyal to Arpagius were allowed to retain their ranks; but most within this category were demoted, and a few were dismissed from the army. All officers above the rank of centurion — as well as some centurions — who had actively participated in combat with supporters of Arpagius were expelled from the army and put on trial for rebellion against Arpagius; and most of these were convicted and sentenced to either life in prison or death. All of the lower-ranking soldiers who had fought on Carausius' behalf were pardoned. All the provincial governors and duces who had sided with Carausius were put on trial, found guilty, and sentenced to either life in prison or death. All of these proceedings were carried out between January and May of 306.

Victory for Arpagius in the civil war meant victory for the Postumians. All of the Princepist senators had sided with Carausius when the war began, and Arpagius replaced all of them with Postumians, except for five who participated in the coup that ended the war. Most of the new senators were Postumians, and those that were not Postumians were affiliated with the "strong leadership" bloc. Likewise, most of the military commanders Arpagius appointed to replace the ones who had supported Carausius were also Postumians. All of the pro-Carausius duces and governors were replaced with Postumians.

Integration of Mauritania Tingitana into the Gallic Empire
Mauritania Tingitana fell to the Gallic Empire with little resistance. The process of integrating Mauritania Tingitana into the Gallic Empire began in April 306. Arpagius had ordered the Gallic forces to ensure that the everyday lives of the locals were not affected by the change in administration. The governor and key military officers and civil administrators were removed from office and replace with Gallic officials, but much  of the provincial bureaucracy continued to be staffed by locals, and local Roman soldiers were invited to join the Gallic army. Also, the new governor of Mauritania Tingitana worked with the governors of the neighboring provinces to integrate Mauritania Tingitana into the Gallic economy.

Relocation of the Capital
In November 308, Arpagius proposed to the Senate that a new capital city be chosen for the empire. After several months of delibation, the Senate voted to designate Tricassium (OTL Troyes) as the new Gallic capital city on March 25, 309. Thereafter, a new imperial palace was constructed. Arpagius and the Senate left Colonia Agrippina on September 6, 318 and arrived in Tricassium on September 19, 318, although the construction of the new imperial palace would not be complete until July 321

Military Reform
After the Gallic Empire broke away from the Roman Empire, its military had been very similar the Roman military. Arpagius carried out two major reforms during his reign. Arpagius began implementing his first reform in 308. The first reform altered the size and structure of army legions. The second major reform was announced in March 316: this was a project to dramatically expand the Gallic navy.

Arpagius also expanded the overall size of the Gallic army. On the eve of the First Gallic Civil War, the army had approximately 160,000 men. After the Third Gallo-Roman War, that number had declined by 15,000. In the decade after the wars, Arpagius took steps to expand the army to 200,000 men.

Expansion of African Territory
During 318, Arpagius launched a campaign to conquer some territory located between the provinces of Amasiga and Mauritania Tingitana. This territory was easily annexed, and it was added to Amasiga. Within a couple of years, a military outpost had been established in that area.

Religious Reforms
Starting in the late 310s, Arpagius began implementing changes to the Gallic state religion to make it more distinctly Celtic. In the late 310s, Arpagius began to de-emphasize the deities that were exclusively Greco-Roman in origin. Then during the 320s, he began promoting Gallic mythology over Roman mythology and Romanized Gallic mythology.

The Franco-Saxon War
The Franco-Saxon War took place between August 314 and May 315. The war began, when bands of Saxons began Frankish lands. Many Frankish villages were devastated. Several Frankish leaders led a counterinvasion in September, but the campaign proved disorganized was quickly repelled. The Saxons then began an effort to drive the Franks out of their territory. By the end of October, the Franks had lost a quarter of their lands to the Saxons. In November, the Frankish chieftains met and chose a young chieftain named Gundisalf to lead the war effort. After Gundisalf was chosen to lead the Franks, the Franks were able to stop the Saxons from advancing further. In January 315, Arpagius sent two legions to Frankish territory to aid the Franks. By late February, all of the Franks' pre-war territory had been won back from the Saxons. The Gallic and Frankish forces then launched a massive punitive campaign against the Saxons that lasted until May.

The Rise of Gundisalf
Like most Germanic tribes, the Franks were not a single polity, but a group of independent chiefdoms. After the Franco-Saxon War, Arpagius felt that it was necessary for the Franks to be consolidated into a unified nation-state with Gundisalf as their leader. Gundisalf agreed to unify the Franks under his rule.

During 316, Gundisalf began forging ties with various people and groups in other Frankish chiefdoms. During the following year, the Gallic Senate passed legislation that changed the trade policy with the Franks so that it favored Gundisalf's chiefdom over others. Little else happened for several years. Then in the summer of 321, Gundisalf orchestrated the assassination of a rival chieftain. The assassination was successfully carried out on July 10, and the chieftain's successor was an ally of Gundisalf. In April 322, a different chieftain allied with Gundisalf killed a rival chieftain and took over his chiefdom. Then in February 324, Gundisalf himself took over a rival chiefdom. In July 326, Gundisalf married the daughter of another chieftain, thereby ensuring that he would inherit control of that chiefdom.

Retirement and Death
During the mid-320s, Arpagius' health began to decline. In February 327, he summoned Tetricus the Younger to Tricassium. Tetricus the Younger arrived in Tricassium in May 327. During the summer of 327, Arpagius began delegating authority to Tetricus the Younger. By the summer of 328, Tetricus the Younger was exercising most of the powers of the First Citizen, though Arpagius retained the right to overrule any decision made by Tetricus the Younger.

On October 7, 329, Arpagius retired and declared Tetricus the Younger the new First Citizen. After retiring, he settled in a village thirty kilometers from Tricassium. He was found dead in his house on July 15, 331.

The Reign of Maximian
The ascent of Maximian to senior emperorship increased the importance of Diocles Valerius, a longtime friend of Diocles who had been very influential within the Roman government ever since Messalla had appointed Maximian Caesar. Diocles had long been a trusted advisor to both Messalla and Maximian, but he had always had less influence over Messalla than Maximian. The death of Messalla essentially led to Diocles becoming Roman emperor in everything but name. During Maximian's time as Supreme Senator, most policies that those two emperors enacted were either formulated or heavily influenced by Diocles.

Personality Cult
For several years before Messalla's death, Diocles had been building a personality cult centered around Messalla and to a lesser extent Maximian. Messalla neither endorsed nor opposed this during his lifetime. After Messalla died, the personality cult intensified. Rome had had an imperial cult since the time of Augustus, but what Diocles advocated was for the imperial cult to be augmented to portray Messalla as greater than all previous emperors except Augustus.

Diocles' propaganda portrayed Messalla as the personification of the values that had made Rome great in the past, the representative of the gods on earth during his lifetime, and having become a god after his death. Similarly, the system of dual rulership was described as ordained by the gods, the appointment of Maximian as Caesar was described as being directed by the gods, and Maximian and all subsequent successors of Messalla were portrayed as inheritors of the role of intermediary between the gods and the people.

Maximian and Maxentius soon embraced the additions to the imperial cult. In accordance with this idea, the two emperors ordered huge palaces to be built for themselves, began wearing ornate purple robes and golden crowns, and instituted elaborate court ceremonies. Temples began to be built in honor of Messalla. May 30, the anniversary of the end of the Great Roman Civil War, was declared the Feast of Messalla.

Monetary Policies and Price Controls
The new denominations of coins that were introduced under Messalla's authority were still less common than the older, debased coins by the time Messalla died. Even those who had significant amounts of the new coins tended to use them only to pay for significant transactions, and used debased coins to finance mundane transactions. In April 309, Maximian attempted to change this by issuing the Edict on Coinage, which outlawed the debased coins, ordered that the debased coins be confiscated and replaced by minting coins of the new denominations by the end of the year, and specified a rate at which debased coins could be exchanged for new ones.

Unbeknownst to Maximian (and Diocles, who proposed the edict), the actual value of the new coins in terms of the old ones was higher than the official rate in some places and lower than the official rate in other places, because different quantities per capita of bronze and copper coins were minted in different jurisdictions. In places where there were not enough new coins, either holders of the old currency were undercompensated for the confiscation, or more of the new coins than necessary to meet the prescribed ratio were minted. Another problem was that the amount of the new currency an individual was entitled to receive was deducted by the amount that he or she already possessed, which meant that much of the old currency was taken without compensation. Since the old currency was still used for everyday transactions, this uncompensated confiscation amounted to losses of wealth for the parties affected. Also, in some provinces, some individuals who had considerably more of the new currency than the equivalent amount of the old currency had the excess amount of the new currency taken from them.

During 309 and 310, wages and prices for every kind of good or service fluctuated wildly as the old coins were replaced: people struggled to correctly value things exclusively in terms of the new currency. Maximiam responded by issuing the Edict on Acceptable Prices, which set price ceilings and price floors for more than two thousand products and services. This caused surpluses and shortages all over the empire. In 314, Maxentius attempted to end these surpluses and shortages by requiring his governors to collect information about the types of goods and services that were rare in their respective provinces; compel people to enter, remain in, or leave certain trades or occupations; and confiscate and distribute goods that people would not voluntarily sell. The governors of several provinces outside the Dominium Caesaris also implemented that policy.

Taxation
Between May 311 and November 312, the tax system was overhauled. Whereas all of Italy had previously been exempted from taxation, henceforward only Rome, Thessalonica, and their suburbs would be exempt. Also, taxes could be paid in various kinds of goods in lieu of money.

Precursors
Christianity had been growing rapidly in the Roman Empire since the 270s. By the 290s, the imperial government began to take notice. In 297, Messalla disqualified Christians from serving as governors or praetorian prefects; and during the 290s, several governors and two praetorian prefects (one of whom was Diocles) carried out purges of the army and bureaucracy within their respective jurisdictions. In 303, Maximian made it illegal to proselytize Christianity within his territory, and Messalla extended this ban throughout the empire a year later. No other actions were taken against Christians at the imperial level for years, although government discrimination steadily intensified in the Dominium Caesaris and various praetorian prefectures and provinces.

Maximian had tolerated discrimination against Christians for years by praetorian prefects and governors for years, but had largely declined to participate himself. The turning point came on May 30, 314, when several Christians protested celebrations of the feast of Messalla. This prompted Maximian to assume a positively anti-Christian stance. In early June, Maximian wrote a letter to Diocles to ask Diocles what measures he thought were appropriate. Diocles, who was preparing to retire, told Maximian that the appropriate model of anti-Christian policies had already been set up in many areas and only needed to adopted and built upon.

The Great Persecution
Although Christians had faced escalating hostility from the state for years, the Great Persecution is considered to have begun on August 2, 314, when Maximian published the First Edict Against the Christians. This law officially set the minimum penalty for proselytizing Christianity at five years in prison, barred Christians from the army and all other state employment, deprived Christians of the right to petition courts or testify in court, made it illegal for Christians to assemble for worship (with violations punishable by no less than five years in prison), and called for the confiscation and destruction of copies of the Bible and other Christian texts. The edict also instructed the Caesar, praetorian prefects, governors, and other officials to take any actions beyond enforcing its provisions that they deemed necessary to repress Christianity; and progressively harsher policies were quickly adopted in many parts of the empire, especially the Dominium Caesaris.

In January 317, Maxentius offered amnesty to imprisoned Christian clergy, provided they offered sacrifices to the Roman deities. This offer was extended to Christians imprisoned for assembling for worship or proselytizing in March. Few Christians actually performed the sacrifices: the wardens of many prisons simply used Maxentius' proclamations as an opportunity to release most or all of their Christian prisoners, and falsely recorded the sacrifices as having been performed. In August 317, Maxentius declared refusing to sacrifice to the Roman deities at least twice a year a capital crime; and Maximian adopted that policy in January 318, titling it the Second Edict Against the Christians. A year later, Maximian published the Third Edict Against the Christians, which made it illegal for non-Christians to protect Christians from arrest or for local authorities to falsely record required sacrifices as having been performed, with the minimum punishment for either action being ten years in prison.

The First Civil War of the Septumvirate
By 320, discontent with Maximian and Maxentius was growing. The consequences of their economic policies had been disastrous. For all the imperial propaganda claiming that Messalla was a god and that Maximian was a representative of the gods, few pagan Romans actually believed these things. The persecution of Christians had failed to wipe out Christianity or even significantly reduce the population of Christians in the empire (and majority of the small decrease in the Christian population that did occur was due to emigration by Christians who lived close to the imperial border). Also, the majority of the pagans did not support the persecution of Christians (which was in fact the reason for Maximian's third edict).

A turning point came on June 7, 320. Ovinius Gallicanus, the governor of the province of Dalmatia announced that he had converted to Christianity, had refused to resign, and would henceforward refuse to enforce the empire's anti-Christian legislation. Between 297 and 314, two other governors had become Christians and immediately resigned, but the governor of Dalmatia chose not to resign because he knew he would be replaced by someone who would enforce the persecutory edicts. Word quickly spread. Several governors of neighboring provinces who were sympathetic to the Christians were impressed with the Dalmatian governor's willingness to defy Maximian. On July 3, the governor of Histria announced that he would end the persecution in his province; and he was followed by the governor of Epirus on July 17 and the governor of Sardeata on July 31. Also, on July 12, the dux of the military district that Dalmatia was a part of announced that he would defy any order to forcibly remove the governor of Dalmatia.

On August 19, 320, the governors of Apulia, Dalmatia, Epirus, Histria, and Sardeata, and a dux from Illyricum and a dux from Haemus (OTL Balkans) met in Salona (OTL Solin). Four days later, they published the Declaration of Salona. In the declaration, they announced that they had formed a seven-member council called the Septumvirate. The Septumvirate would lead a rebellion against Maximian and Maxentius, and then act as a provisional government. The members of this council agreed to end the imperial-level persecution of Christians and prohibit all local persecution, grant Christians equal rights under the law, and repeal the Edict on Acceptable Prices and the mandate for governors to institute economic planning. The members of the Septumvirate agreed to elect a new Supreme Senator after overthrowing Maximian and Maxentius, and then disband.

Promising to repeal the worst of Maximian's economic policies made the Septumvirate very popular. During September in Italy, Africa, and the Balkans, many army units declared allegiance to the Septumvirate, civilians began forming pro-Septumvirate militias, and the governors of Calabria and Dardania defected to the Septumvirate. In late September, Maximian launched an invasion of Septumvirate-controlled provinces. At the same time, militias in many cities and towns in Rome's European and African provinces began fighting to overthrow local officials.

Maximian and Maxentius rapidly lost territory to the Septumvirate due to defections, conquests, and popular uprisings. By February 321, the Septumvirate controlled all of Illyricum, most of southern Italy, northeastern Italy, eastern Sicily, northwestern Haemus, Egypt, Zeugitana, Cilicia, Pontus, parts of Galatia, and Cyprus. Then in early February, a stalemate emerged in Italy, Africa, and the Balkans (although the Septumvirate steadily gained territory in the Levant and Anatolia). This stalemate lasted until late April. On April 22, the residents of Rome rose up against Maximian. By April 25, militias and defecting army units had taken control of several parts of the city, and Maximian had fled for Florentia (OTL Florence). At the same time, Maxentius had begun a large-scale offensive in the Balkans. During May, the Septumvirate gained control of central Italy and western Sicily, but lost parts of Dardania and Epirus. Maxentius' offensive continued in early June, but he was forced to partially pull back when the governor of Galatia surrendered to the Septumvirate.

During June and July, Maximian and Maxentius held their ground against further advances by the Septumvirate and its supporters. Also during this time, Maximian and Maxentius began to ease their persecution of Christians. On June 18, Maximian repealed the Second and Third Edicts Against the Christians (although he did not forbid or even discourage the continued implementation of its provisions by the governors or praetorian prefects who were still loyal to him). On July 9, Maxentius issued an unconditional amnesty for Christians who were imprisoned within the Dominium Caesaris. This, however, fell far short of the full equality under the law that Christians had already been granted in the areas under the Septumvirate's control. Also, Maximian and Maxentius still failed to realize how unpopular their economic policies were and left them unchanged.

On July 28, the praetorian prefect of Mauritania was removed from office in a coup staged by the governor of Mauitania Sitifensis, who then declared himself praetorian prefect and declared allegiance to the Septumvirate. He and his supporters eliminated all resistance within three weeks. On August 15, he sent a legion to invade northern Italy. These soldiers arrived in Italy on August 22. Maximian fled from Florentia on August 27. His plan was to move to Genua (OTL Genoa); but by the time he arrived, on September 3, the local army commanders were already preparing to surrender. They offered to have him hidden and ensure that he would enjoy a comfortable retirement in exchange for his resignation. Maximian accepted the offer.

As news of Maximian's disappearance spread, governors and praetorian prefects who had remained loyal to him rapidly began either surrendering or defecting. Maxentius refused to surrender though. Out of desperation, Maxentius relaxed the price controls on October 5 and repealed the First Edict Against the Christians on October 9, but it was too late. By November 12, Thessalonica was surrounded. On that day, his generals killed him, surrendered to the Septumvirate, and then killed themselves.

Beginning of the Celtic Renaissance
During the 290s, the governors of Aremorica, Lexovia, Aulercia, and Pictonia placed Gaulish on par with Latin as an administrative language. The governor of Belgica made Gaulish an administrative language in 302, and the governor of Senonium would do likewise in 303.

The effects of the policy on administrative languages began to manifest itself in the 320s. By that time, it had become necessary for the provincial elites to be able to understand Gaulish. Government documents were written in both Latin and Gaulish in the Gallic Empire's northern continental provinces. Also, privately-written texts that were originally written in Latin or Greek were being translated into Gaulish. Then in 324, a Belgican author wrote the first book to be originally written in Gaulish (it would not be translated into Latin for more than two decades).

The revival of the Gaulish language coincided with Arpagius' efforts to make the empire's state religion less Roman and more Celtic. The governors of the northern Gallic provinces and the Britannian provinces had preserved pre-Roman Celtic myths, beliefs, and practices in their capacity as presiders over local religions ever since the conquest of Gaul by Julius Caesar. Although took steps Arpagius to make the state religion more Celtic, the governors of Aremorica and Pictonia went further, promoting Celtic religious ceremonies and burial customs over Roman ones.

The 320s marked the beginning of the Celtic Renaissance. This would be a time period during which the culture of the northern parts of the Gallic Empire would become less Latin and more Celtic. Although this cultural shift was concentrated in northern and central Gaul, it would later spread to Britannia, and have a limited influence on the empire as a whole.

Spread of Christianity
On the eve of the Great Persecution, Christians comprised sixteen percent of the Roman Empire's population. By the time the persecution was over, their portion of the empire's population had declined to fourteen percent. Most of the net decline was due to emigration. Although many Christians were executed during the persecution, a few pagans converted during this time.

Outside the Roman Empire, Christianity spread rapidly during the first quarter of the fourth century.

In Armenia, King Tiradates III became a Christian in 301 and quickly declared Christianity the state religion. Prior to the king's conversion, Christians had made up less than ten percent of the population. By 325, Christians accounted for over forty percent of the population. During the Great Persecution, many Roman Christians fled to Armenia, and Tiradates III sent a letter to Maximian condemning the persecution.

In Iberia, Christianity had had a small presence since the first century. Significant growth did not start until the 310s, when Tiradates III of Armenia sent missionaries into Iberia. By 325, approximately one eighth of the population was Christian.

In Osroene, Christians comprised roughly twenty percent of the population in 300. Christianity had grown to almost thirty percent of the population by 325, due to both immigration from the Roman Empire and proselytization. The government of post-Roman Osroene had always been tolerant of Christianity, and many Christians served in the state's army and bureaucracy.

The government of Persia had always been indifferent towards Christians, and several large Christian communities existed in Mesopotamia by 300. During the Great Persecution, some Roman Christians migrated to Mesopotamia. The Arab kingdom of Lakhm, an ally of Persia, had always been majority-Christian.

Christianity had always been legal in the Gallic Empire. During the Great Persecution, many Christians migrated to the Gallic Empire, particularly eastern Spain and southern Gaul. By the time the persecution ended, Christianity's share of the Gallic Empire's population had grown from 12% to 17%.

The Reign of the Septumvirate
On September 1, 320, the Septumvirate issued the Edict on Full Toleration of Christians, which not only repealed the imperial Edicts Against the Christians and banned all persecutory legislation issued by levels of government below the imperial, but also officially declared Christianity to be a legal religion and declared Christians to be equal under the law in all respects. On October 3, 320, the Septumvirate issued the Edict on Buying and Selling, which repealed the Edict on Acceptable Prices and the Maxentius' edict calling for provincial governors to institute planned economic systems. After the Septumvirate issued the Edict on Buying and Selling, the governors in most of the provinces controlled by the Septumvirate quickly began deregulating the provincial economies. After the downfall of Maxentius, the Edict on Full Toleration of Christians and the Edict on Buying and Selling entered into force throughout the Roman Empire.

In December 321, the members of the Septumvirate moved to Rome to govern the empire. Upon arriving in Rome, the council announced that it would choose a new emperor by December 322. During 322, the Septumvirate met many times to discuss who to appoint. In March 322, they agreed to maintain the system created by Messalla, and appoint both a Supreme Senator and a Caesar.

In May 322, the Septumvirate issued the Edict on the Priesthood. This law reestablished the office of Pontifex Maximus as a legally separate office from that of Supreme Senator, but authorized an individual to hold both offices simultaneously. Similarly, the law also established the offices of Pontifex Magnus and Pontifex Provincialis as distinct from the offices of Caesar and provincial governor, respectively. The Septumvirate issued this edict at the urging of Gallicanus: Gallicanus reasoned that if the emperors or provincial governors were obligated to organize and preside over pagan ceremonies, then Christians, who would find participating in such ceremonies objectionable, would effectively be disqualified from those offices. (In fact, in the Gallic Empire, Christians were explicitly disqualified from the offices of First Citizen and provincial governor because those offices had religious functions.)

During 322, the Septumvirate faced two rebellions, one staged by the governor of Liguria from February through March, and another one staged by the two generals in Moesia that lasted from June until September. Both rebellions were quelled rather easily, because in each case the rebel leader failed to gain popularity. Another problem that arose during 322 was that conservative pagans began staging anti-Christian riots in numerous cities throughout the empire. Four governors were removed from office for neither attempting to quell the riots nor prosecuting those involved, and two of those four were sent to prison. The Septumvirate also sent agents to search for Maximian.

On December 6, 322, the Septumvirate announced who they had chosen to appoint as the new emperors: Valerius Maximus Basilius as Supreme Senator and Flavius Ablabius as Caesar. Maximus Basilius had served as Urban Prefect of Rome since 317 (an unusually long tenure) and held several governorships before that. He did not defect to the Septumvirate until they took over Rome, but the Septumvirate chose to retain him as urban prefect because they considered him a competent administrator and deemed him unlikely to turn against them. Ablabius was the governor of Cilicia and an early supporter of the Septumvirate. Maximus Basilius accepted the appointment, and the Septumvirate stepped down on December 12.

Religion
Shortly after Maximus Basilius became Supreme Senator, he announced that Christianity would remain legal and that Christians would retain their newfound equality under the law. (The Septumvirate had chosen him because they anticipated that he would do this.) He did, however, take the office of Pontifex Maximus, and expressed a desire to promote paganism over Christianity (and other religions).

In 325, Basilius published a book titled The Declarations of the Gods. He intended for this book to be a codified scripture for Roman paganism, a pagan counterpart to the Christian Bible. The Declarations covered a wide range of topics, including mythology, history, ethics, metaphysics, epistemology, logic, and political philosophy. It discussed matters such as the Roman Empire's place in the world, the reigns of Messalla and Maximian, and the political systems of the Roman Empire and several other states. The book included an attempt to reconcile the Roman state religion with the increasingly Celtic-influenced Gallic state religion, and numerous arguments against Christian theology.

Despite Basilius' efforts to promote The Declarations of the Gods, the book was controversial even among pagans. The majority of the content of The Declarations was either a verbatim copy or paraphrase of earlier works, something which several pagan scholars quickly pointed out. Also, there were many pagans who did not see any need for a comprehensive religious text. People who held philosophical views different from those expressed in The Declarations rejected or criticized the book on those grounds. The Declarations was largely ignored in the Gallic Empire. Christian theologians quickly wrote responses to the arguments against their faith made in The Declarations.

Roman-Gothic Wars
In 271, Emperor Aurelian had released the province of Dacia from Roman control and encouraged the inhabitants, most of whom were Latinized, to settle south of the Danube. After the abandonment of Dacia, the Goths settled in the southern part. Both during and shortly before the Great Persecution, many Christians in the Balkans migrated to Dacia to escape persecution, and most of them remained there after the persecution ended.

Bands of Goths had staged small, infrequent raids in the Balkans since the 280s. In August 326, however, a large army of Goths began a massive invasion of Moesia. It was the largest Germanic invasion since 269. Ablabius led a massive force to repel the invasion. By January 327, the Goths had been driven out of the Balkans.

In March 327, the governor of Moesia launched a punitive campaign against the Goths without authorization by Ablabius of Basilius Maximus. Since the attack was unauthorized, Ablabius quickly replaced the governor of Moesia and sent an envoy to the Goths to apologize, but the Goths rejected the apology. In June 327, the Goths again invaded the Balkans, this time with soldiers from neighboring tribes joining them. This time the invaders penetrated as far south as Thrace. It took the Romans until August 328 to completely drive the Goths out of the Balkans. Shortly before the Goths left the Balkans, they staged a naval attack on northern Anatolia. The attacks on the Anatolian coast were quickly fought off by provincial armies.

In September 328, Maximus Basilius ordered Ablabius to lead a campaign to reconquer land north of the Danube. The invasion began in January 329. Ablabius led two legions into Gothic territory from the south, while two other legions invaded from the east. By April 330, the Romans had occupied all land south of the Southern Carpathian Mountains and the Musius (OTL Buzău) River, and expelled the Goths from this area.

Ablabius reestablished the province of Dacia, and incorporated the province into the Dominium Caesaris and the praetorian prefecture of Haemus. Since the majority of the non-Gothic inhabitants of the area were Christians who had emigrated from the Roman Empire, Ovinius Gallicanus asked Ablabius to make him the governor of the province in order to win the trust of the locals. Ablasius granted Gallicanus' request.

Assassinations
Maximus Basilius never trusted the former members of the Septumvirate. He reasoned that since the Septumvirate was powerful enough overthrow the previous emperor and appoint him emperor, they would be powerful enough to depose him if they ever chose to do so. Two things that added to his concern was that the members of the Septumvirate had maintained close contact with each other ever since terminating their provisional rule over the empire, and they continued to be very popular. By 328, Basilius decided to have the former members of the Septumvirate killed.

Basilius did not want it to be obvious that he was responsible for the assassinations, for fear of provoking a rebellion, so he spent a couple of months planning how to eliminate the Septumvirate. He decided to have one of them killed at a time. To make it less obvious that he was targeting the Septumvirate, he also decided to have several other prominent officials killed, and he decided to have the assassins arrested. Each assassination would occur two to four months apart.

The first assassination of a member of the Septemvirate occurred on August 22, 328. A second member of the group was killed on March 12, 328. A third member was killed on November 12, 329. Between each assassination of a Septumvirate member, two to five other prominent officials were killed.

The Second Civil War of the Septumvirate
After the third assassination of a Septumvirate member, the surviving members of the group began to investigate the deaths of their friends and former colleagues. Though the surviving members never found any evidence that clearly Basilius to the murders, they did learn enough to convince two of them that he was orchestrating the killings. Those two members, Flavius Turullius Didicus and Vettius Aurelius Abito, began organizing a rebellion against Basilius.

On February 3, 330, Didicus and Abito announced that they no longer accepted Basilius as Supreme Senator because of his role in the string of political assassinations that had occurred over the prior year and a half. This occurred only days before a fourth member of the Septumvirate, Aulus Avitus Caepio, was to be killed. Caepio had not been convinced that the Septumvirate members were being targeted for assassination, but after he learned that a rebellion was underway he feared for his life and fled to a city held by his former colleagues and joined the rebellion.

Even though the Septumvirate had remained immensely popular among both the military and the civilian population, it quickly became clear that rebelling against Basilius would be more difficult than rebelling against Maximian. Unlike Maximian, Basilius was not tyrannical, and the partial reconquest of Dacia had made Basilius popular. Ovinius Gallicanus chose to throw his lot with Basilius. The only generals and political officeholders who joined the rebellion at first were friends and relatives of the assassinated officials.

By June 330, the war was going badly for the Abito, Caepio, and Didicus. Very few generals had joined them since April, and they were steadily losing territory. Out of desperation, they appealed to Ablabius for help. They offered to accept Ablabius as Supreme Senator, in return for him appointing one of them the new Caesar. At the same time that they made this proposal, a provincial governor with ties to Abito started disseminating propaganda falsely claiming that Ablabius and several generals had already chosen to turn on Basilius. In July 330, army units under the direct control of Basilius began attacking units from the Dominium Caesaris. This prompted Ablabius to rebel against Basilius in August 330, although he did not join Abito, Caepio, and Didicus. Some of the generals accused of betraying Basilius defected to the former Septumvirate members, others threw their lot with Ablabius.

Between August 330 and November 330, Basilius, Ablabius, and the former Septumvirate members fought a three-way war. The ex-Septumvirate members did not attack the territories held by Ablabius, as they hoped to persuade Ablabius to join forces with them; Ablabius, however, had his forces attack both the territories held by the former Septumvirate members and those held by Basilius. Abito, Caepio, and Didicus steadily lost territory to both Basilius and Ablabius during this time, but Basilius and Ablabius were locked in a stalemate. Finally, on November 9, Ablabius sent a letter to Abito, Caepio, and Didicus in which he agreed to join forces with them. He had conditions for allying with them: the governor who falsely accused Ablabius of turning against Basilius would have to be imprisoned, and the three former Septumvirate members would be expected to retire from politics immediately after the war. The former Septumvirate members accepted Ablabius' terms. At the same time that Ablabius was negotiating with the Septumvirate, he began attempting to persuade Flavius Vipsanius, a distinguished general, to defect from Basilius, promising to appoint him Caesar. Vipsanius accepted Ablabius' offer.

By January 331, Ablabius and his allies had begun to gain ground against Basilius. For a time, Ablabius' advance was relatively slow. The turning point was the Battle of Ravenna in April 331, in which forces loyal to Basilius lost the city to a smaller pro-Ablabius force. After the Battle of Ravenna, two governors in northern Italy defected to Ablabius, and forces loyal to Ablabius quickly advanced toward Rome. Basilius fled Rome for Carthage on April 24, and ordered the generals loyal to him to evacuate their forces from Italy to the north African provinces.

By July 331, Ablabius was in control of all of the Roman Empire except for several African provinces. Many of the army units loyal to Basilius had relocated there. Between August and October, Abalbius' forces made several attempts to invade Basilius' remaining territory, but those invasions were repelled. By the end of the year, Ablabius decided to postpone his efforts to take the African provinces. This stalemate would last for several years.

After the Civil War
The Second Civil War of the Septumvirate ended with the Roman Empire divided between Basilius and Ablabius. Basilius retained control over the provinces of Zeugitana, Byzacena, Numidia, Mauritania Sitifensis, and Mauritania Caesariensis, and ruled from Carthage; while Ablabius took up residence in Rome and ruled over the rest of the empire. Ablabius appointed Vipsanius as his Caesar. Basilius never appointed another Caesar.

Little happened for a year after the war ended. Both emperors, realizing that neither could overthrow the other, turned their attention to administering their portions of the empire.

After the war, Arpagius banned all commerce with Basilius' provinces. This left Basilius' territory economically isolated. In early 333, Basilius authorized his provincial governors to begin building trade relationships with the Gallic Empire's African provinces and Baetica in order to obtain goods and resources that Basilius' provinces had been cut off from.

Basilius died of food poisoning on February 17, 336. As his death was unexpected, he had never designated a successor. Thus, his territory fell into chaos. Five major factions arose: three of them were each led by a man who wanted to rule northwestern Africa and eventually take over the rest of the Roman Empire, one was led by two generals who defected to Ablabius, and one was led by a general who wanted western Africa to be permanently independent and aligned with Gaul. Minor factions included at least one secessionist group for each province and several republican factions. This civil war did not last long. In June, Ablabius sent three legions into western Africa. By September, Ablabius' forces had overrun all the factions and taken control of the entire region.

Administrative Reforms
During the 290s, Messalla made significant reforms to the empire's administrative structure in order to make rebellions more difficult, but several major rebellions had still occurred. In 333, Ablabius further changed the administrative structure of the empire.

Provincial governors would no longer have any direct authority over provincial military forces. Instead, the provincial military forces would be commanded by a new officer known as the magister militum provincialis, though that officer would be appointed by the provincial governor. Also, provincial governors would no longer have any judicial powers. Instead, the governor of each province would appoint a supreme judge, who would exercise the judicial powers formerly exercised by governors. Autonomy was granted to major cities, and governors were required to appoint urban prefects to administer the cities. Finally, Ablabius initiated a policy of frequently rotating province-level officeholders and urban prefects from one province to another, and military commanders from one unit to another. (For example, an urban prefect in one province would typically not subsequently be able to serve as an urban prefect of another city in the same province, but could easily be chosen to serve as an urban prefect of a city in a different province.)

The reason for limiting the authority of the provincial governors was to prevent any governor from gaining the prestige necessary to rebel. The reason for frequently rotating officials between provinces was to prevent officials from forming relationships that would facilitate the trust and cooperation necessary to stage a rebellion. These administrative reforms would finally solve the problem of frequent uprisings against imperial authority. Unfortunately, they would also have the effect of producing administrators who could never understand the needs or culture of the provinces they governed, as well as military commanders who could never gain strong loyalty or respect from the units they commanded.

Foreign Policy in the Middle East
Ever since 282, Osroene, formerly a province of Rome, had been an independent kingdom allied with Persia. Under Messalla, Rome had tried to reconquer Osroene and failed. Ablabius hoped to maneuver Osroene back into Rome's sphere of influence by building economic ties with Osroene. In 335, he instructed the governors of the Levantine provinces to provide financial incentives for local merchants and craftsmen to sell their products in Osroene.

Ablabius also worked to forge ties with Arab states and tribes. He was particularly interested in the nascent Ghassanid kingdom, which bordered Palestine. Ablabius saw Ghassan as a potential counterweight to Lakhm, and Arab state allied with Persia.

Western Africa
After Ablabius took over the provinces that had remained loyal to Basilius, he quickly consolidated his authority over the region. One of the generals who had wanted to maintain the status quo was charged with treason and executed, while the other two were ordered to resign from the army. The leaders of all the republican and secessionist militias were declared traitors and executed. The two generals who had sided with Ablabius after Basilius died were rewarded: one was made praetorian prefect of Africa, while the other was made a dux over western Africa. Ablabius filled all the other major civil and military offices with people who had been loyal to him since his initial uprising against Basilius.

In 337, Ablabius implemented his administrative reforms in western Africa. That same year, he banned all trade with the Gallic Empire, except for Amasiga, which Ablabius declared to have been conquered by rebels. (The Roman Empire had never recognized the Gallic Empire as independent.)

Religious Policy
Under Ablabius, Christianity remained legal, and Christians continued to have full equality under the law. Ablabius himself was a pagan. Like Basilius before him, Ablabius took the office of Pontifex Maximus.

On several occasions, Ablabius criticized The Declarations of the Gods, the book Basilius had written as a pagan scripture. Many historians would later argue that Ablabius' opposition to The Declarations was motivated more by politics than his personal beliefs, because in several letters and speeches he expressed views that were similar to ideas expressed in The Declarations.

Conversion of Vipsanius to Christianity
On October 2, 339, Caesar Vipsanius announced that he had converted to Christianity. Shortly after Vipsanius announced this, several pagan governors and generals inside the Dominium Caesaris expressed concern about their rights and the rights of other pagans, either in letters to Vipsanius, Ablabius, or the praetorian prefect whose jurisdiction they were under. This concern was heightened on December 16, 339, when Vipsanius gave a speech outside the largest church in Thessalonica in which he invited his audience to "learn about the one God of all heaven and earth, and also Jesus Christ."

On February 6, 340, Ablabius announced that he did not object to Vipsanius' conversion, and ordered the people of the Dominium Caesaris to continue to obey Vipsanius as long as he did not rebel against Ablabius or persecute pagans. On February 12, Vipsanius declared that he would respect the rights of pagans and that he would not discriminate against pagans with regard to appointment to civil or military offices, and he also reaffirmed his loyalty to Ablabius. These proclamations from Ablabius and Vipsanius largely diffused the concerns of pagans.

The Reign of Tetricus II
Tetricus II (previously known as Tetricus the Younger) became First Citizen of the Gallic Emperor following the retirement of Ablabius on October 7, 329. He was the first Gallic emperor who was a biological descendant of a prior emperor. (His father was emperor Tetricus I.)

Unification of Francia
During the 320s, Gundisalf (with the support of Arpagius) had worked to unify the Franks under his rule. After Tetricus II became emperor, he continued the Gallic Empire's support of Frankish unification.