Gaul Rising

This is an alternate timeline in which the Gallic Empire, which in our timeline was a short-lived breakaway state from the Roman Empire, manages to hold on to its independence.

Author's note: I would appreciate any suggestions you have. You can either post suggestions on the article's discussion page or my own talk page. I am also okay with you making minor edits, such as spelling or grammar corrections; but I would prefer that nobody other than me make major additions or revisions. Thank you and enjoy this timeline.

 Pacificus   Viridis 

The Crisis of the Third Century
For much of the Third Century, the Roman Empire was in a constant state of civil war.

It began in 235 AD, when Emperor Alexander Severus was murdered by his own troops, who felt he was not being aggressive enough in dealing with a Germanic invasion of Gaul. Alexander Severus' forces declared Maximinus Thrax the new Emperor. Thrax was not popular in the Roman Senate, so when Gordian, the governor of the province of Africa Proconsularis, rebelled in 238, the Senate proclaimed him and his son Co-Emperors. The rebellion failed, but the Senate appointed another pair of Co-Emperors as Thrax was preparing to march on Rome to punish the Senate. The Senate's choices were unpopular among the masses, so the masses declared Gordian's grandson Emperor. This led to anarchy in the city. Meanwhile, Thrax's invasion of the city failed, so his troops killed him out of dissatisfaction.

The downfall of Alexander Severus, the reign of Maximinus Thrax, and the rebellion of Gordian I and Gordian II were the start of a vicious cycle in which a general or provincial governor would rebel against the current Emperor, possibly gain the acceptance of the Senate, immediately have to deal with an external invasion or rebellion, and in many cases be killed by his own troops, who would then align themselves with a new contender for the throne. Generals turned their attention more toward fighting each other than protecting the Empire's external borders, which led to frequent invasions by barbarian tribes. Another problem that resulted from the constant civil war was severe inflation: each time someone would declare himself Emperor, he would promptly have a large supply of coins with his face on them minted to pay his troops. This state of affairs lasted for decades.

The Rise of Postumus
Marcus Cassianius Latinius Postumus was appointed governor of the Roman border province of Germania Inferior by Emperor Valerian during the 250s. Valerian ruled from 253 to 260 alongside his son, Gallienus. After Valerian died, Gallienus reigned alone. In 258, Gallienus appointed his son, Saloninus, a subordinate emperor.

In 260, Valerian was waging a campaign against Persia (which resulted in his capture and execution by the Persians) and Gallienus and his forces went to Pannonia to deal with a rebellious general. Postumus, Saloninus, and Saloninus' mentor, Silvanus, were tasked with defending the Rhine frontier. They were stationed at Colonia Agrippina (Cologne).

Now on October 25, 260, Postumus and his forces intercepted an army of Juthungi (a Germanic tribe) that was returning home from a battle at Mediolanum (Milan). The Juthingi had lost the battle but nevertheless managed to carry off captives and other booty. Postumus's army defeated the invaders and then divided their loot among themselves. Saloninus, at the recommendation of Silvanus, ordered Postumus to hand over the loot to him. Postumus and his troops refused, and Postumus' troops declared him Emperor on November 2. Postumus and his army then laid seige to Colonia Agrippina. On December 9, Saloninus and Silvanus surrendered and allowed Postumus and his forces into the city, and were thereafter executed. Ever since then, December 9, 260 has traditionally been considered the date that Postumus' reign officially began.

Postumus was immediately recognized as Emperor in the Gallic provinces (except for Gallia Narbonensis), Germania Inferior, Germania Superior, and the Alpine province of Raetia. Within a year, the Britannian and Spanish provinces also aligned themselves with Postumus; and Gallia Narbonensis followed a year later. Postumus made Colonia Agrippina the capital of his realm and set up a system of government similar to that of Rome as it was before the death of Alexander Severus. The coins minted under his authority were of an unusually good quality for coins for those days. Rather than seeking control of the rest of the Roman Empire, Postumus focused on defending and bringing stability to the provinces he ruled; and he was indisputably successful at achieving this goal.

Gallienus had to leave Postumus alone for several years, as Germanic tribes were constantly invading the areas still under his control. He challenged Postumus for the first time in 265, sending Aureolus, a general loyal to him, to invade the breakaway provinces. The campaign failed as a result of carelessness on the part of Aureolus. Two years later, Gallienus himself invaded Postumus' realm, but this invasion also failed. Gallienus did manage to retake Raetia in the latter half of 266.

Point of Divergence
The point of divergence between this timeline and ours occurs in 268. Aureolus, who was at that time stationed in Mediolanum (Milan), openly defected to Postumus. Gallienus promptly led an invasion of Mediolanum.

What Happened in OTL
Postumus chose not to come to Aureolus' aid. Gallienus' forces laid seige to Mediolanum. During this time, Gallienus' senior officers murdered him and proclaimed Marcus Aurelius Valerius Claudius (Claudius Gothicus) Emperor. Aureolus surrendered to Claudius II, only to be executed thereafter.

Postumus' decision not to help Aureolus marked the beginning of the end of his rule. His armies became discontented with him, which is evidenced by a sudden decline in the quality of the coins issued under his authority in 268: he had more coins produced in an effort to buy the loyalty of his troops. One of his generals, Laelianus, declared himself Emperor. Laelinus was stationed in Moguntiacum (Mainz), so Postumus led forces that were still loyal to him to invade Moguntiacum. Postumus defeated Laelinus, but then forbade his soldiers to plunder the city. For this, they murdered him and proclaimed Marcus Aurelius Marius the new Emperor.

Thereafter, the territory Postumus had controlled fell into the same state of disorder that the Roman Empire as a whole had fallen into more than thirty years before. Postumus' realm became increasingly weak; and in 274, Roman Emperor Aurelian reconquered what was left of it.

What Happened in This Timeline
Postumus decided to lead a campaign to Mediolanum to help Aureolus out. The combined forces of Postumus and Aureolus managed to repel Gallienus' campaign. Gallienus' senior commanders, who wanted him dead anyway, murdered him and proclaimed Marcus Aurelius Valerius Claudius the new Roman Emperor.

The Remainder of the Reign of Postumus
Postumus' victory at Mediolanum was an important one. The direct result of the victory was that he now had an ally in Aureolus and control of Mediolanum and the surrounding area. Postumus never intended to invade Rome; but he did anticipate that doing so could be necessary as a defensive action, and Mediolanum would be an important point from which to launch such an invasion should he deem it necessary. Also, Postumus would now be able to invade Raetia on two fronts, one being from the west and the other being from the south. The area also served as a buffer between Roman territory and Postumus' core territory.

Claudius II, the new Romen Emperor, had to immediately turn his attention to the Balkans and the Agean Sea, where various Germanic tribes were carrying out a massive naval invasion. Claudius II was able to drive out the invaders after the Battle of Nassius. This was an important victory for the Roman Empire as it neutralized the threat of the Germanic tribes north of the Danube for more than a decade. After the victory, Claudius II took the title "Gothicus".

Shortly thereafter, an army of Alammani and Juthingi invaded Raetia. Armies loyal to Postumus came to the aid of the forces stationed in Raetia before Claudius II could arrive, and the combined forces sucessfully repelled the invasion. The governor of Raetia, in gratitude, aligned himself with Postumus.

Claudius II began planning to invade Postumus' realm, but he was forced to put his plans on hold in order to travel to Pannonia to deal with Vandal raids. Before he could engage the Vandals, however, he died of smallpox in January 270. He was succeeded by his brother, Quintillus, who in turn died and was succeeded by Aurelian by September 270.

Early Administrative and Constitutional Reforms
In 271, Postumus established a clear procedure for imperial succession. This was an important constitutional reform, because one of the original causes of the political instability in the Roman Empire was a lack of such a formally defined procedure, so the establishment of a formal process offered the promise that Postumus’ empire could remain internally stable long after his death. It was also significant because it gave the Senate some say in the process of imperial succession. The guidelines he established were as follows: the Emperor could designate a person to succeed him upon his death or abdication; and if the Emperor were to die or abdicate without a designated heir, the Senate would have the exclusive power to elect a new Emperor. In 274, he also gave the Senate the power to depose the current Emperor, provided that the Senate first come to an agreement upon who the new Emperor should be. The purpose of this second edict was to discourage armed rebellions against unpopular Emperors.

Postumus also began reorganizing the provinces under his rule during this time. At first, the changes he made were rather modest. In 271, he divided the province of Lugdenensis into smaller provinces. Then in 273, he formed two new provinces from parts of Aquitania. More significant reforms, including changes to the actual administrative structure of the provinces, would come later.

The Gallic War for Independence
Main article: Gallic War for Independence

Prelude
At the time that Aurelian became Roman Emperor, Postumus was still in a very good position. From his capital in Colonia Agrippina, he ruled over Gaul, Spain, Britannia, Raetia, and the majority of the northwestern Italian region of Transpadana (this was the area that surrounded Mediolanum). He had successfully defended his domain from external invasions. While the main empire was still tormented by civil war and external invasions, Postumus' empire was enjoying a state of stability and prosperity unknown since the death of Alexander Severus. Postumus' popularity had grown, especially after his battle against Gallienus at Mediolanum and the campaign against the Germanic invaders of Raetia that led to Raetia voluntarily rejoining his empire.

Yet Postumus' success was partially the result of mere luck. If Gallienus did not have to spend several years fighting off Germanic invaders, he could have confronted Postumus before Postumus had a chance to consolidate his authority. The invasion led by Aureolus in 265 mainly failed as a result of carelessness on his part. Gallienus had managed to defeat Postumus by retaking Raetia in 266, though Postumus reversed that defeat in 269. Postumus would not be in control of Mediolanum if Aureolus had not defected to him, and maintaining control of Mediolanum would have been more difficult for Postumus if Claudius II had not had to deal with the major Germanic invasion in the east. It was from Aurelian that Postumus would receive his first major challenge.

Aurelian did not take any action against Postumus until 275. For the first couple of years of his reign, he successfully contended with Germanic invaders. Then in late 272 and early 273, he turned his attention to recovering Egypt and the Asian provinces, which had become part of a breakaway empire similar to that of Postumus. Aurelian was able to bring the entire breakaway empire, known as the Palmyrene Empire, back under Roman rule in a matter of months. One action considered a key to his rapid victory over the Palmyrene Empire was that he had refrained from sacking the city of Tyana after taking control of it. As a result of the mercy he showed to Tyana, many other cities in the Palmyrene Empire opted to peacefully surrender. Aurelian conducted several other campaigns after this one, and then prepared to go to war with Postumus.

275
The war began in March 275, with Aurelian's armies invading Postumus' domain on three fronts: Baetica, Narbonensis, and the Alpine provinces. Aurelian personally led the invasion of Narbonensis. At first, Aurelian's forces were successful on all three fronts.

By the middle of May, however, all three groups were losing momentum. The Alpine invasion actually turned out to be a complete fiasco, because Aurelian's spies had underestimated Postumus' defenses in the area. In Baetica and Narbonensis, the armies loyal to Postumus managed to slow down Aurelian's forces. The military itself in Postumus' realm was growing, because many people in those areas were strongly loyal to Postumus and voluntarily enlisting in order to defend him.

Postumus knew that fighting off Aurelian's all-out invasion would not be easy, so he decided to reach out to several Germanic tribes for help. He sent envoys to the Alamanni, Suevi, Marcomanni, and Quadi in late April. The envoys were instructed to propose an alliance between the tribes and Postumus' empire. The plan was for the tribes to invade Pannonia Superior, Pannonia Inferior, and Noricum; and in return, Postumus would consent to those tribes permanently controlling the territory of those three provinces, so long as they did not subsequently invade his territory. The Suevi declined the offer; but the other three tribes accepted, but only on the condition that Postumus develop and execute a workable plan for his own forces to invade another area under Aurelian's control.

In order to meet the demands of his potential allies, Postumus planned a massive invasion of Italy in May 275. In fact, he had already ordered some units to sneak into Italy, a few men at a time, between 271 and 273; so that he would have troops already in Italy should he ever deem any campaign in the Italian peninsula necessary. He decided this "sleeper army" would not be sufficient for a campaign of the size he was planning, however. He decided to send a large naval force to central Italy, order a land invasion from Transpadana, and have the sleeper army operate in the southern part of the peninsula. All three groups were to use scorched earth policies, and the invaders coming from the north and the center were to converge on Rome and sack it.

The invasion of Italy began on July 17, when the sleeper army began wreaking havoc in southern Italy. Postumus' forces began a seige of Rome on July 24, and broke into the city by August 19. The sack of Rome lasted until September 6, after which the forces under Postumus' command left and went on to plunder other cities in central and northern Italy. The invaders that entered Italy from the sea and from the north reached Raetia by November, although a quarter of them died along the way. The entire sleeper army was killed or captured in late September, just before it could escape to northern Italy.

The invasion of Italy was an important turning point in the war. It forced Aurelian to send some of his men to Italy and away from Postumus' empire, even to the extent of completely pulling out of areas that Aurelian's armies had already secured. Also, the success of the invasion caused the Roman military to begin losing faith in him; and in early October, Marcus Aurelius Probus and Faltonius Pinianus each declared themselves Emperor. It also convinced the Alamanni, Marcomanni, and Quadi that Postumus was worth supporting, and the three tribes began invading Pannonia and Noricum in late October 275.

Aurelian's soldiers and officers in Gaul and Spain continued to recognize him as Emperor, but they began losing confidence in him. One reason was because of how terribly Italy was devestated, and the other reason was because the campaigns in Gaul and Spain were progressing too slowly. The last straw came at the end of 275, when Postumus' forces and local resistance cells won back southern Spain from Aurelian in just a few weeks. When Aurelian's senior staff in Gaul learned of this, they decided that they had had enough of Aurelian. Aurelian's reign came to an end on December 27, 275: he was beaten, put in a cage, and deposed. Julius Asclepiodotus declared himself the new Roman Emperor, and his first act was to pull out of Gaul completely.

The Gallic Declaration of Independence
Up until this point, while Postumus had on the one hand refused to recognize the authority of the official Roman Emperors, and on the other hand made no effort to take over the entire Roman Empire; he had never actually declared his territory to be seperate from Rome. This changed on January 14, 276, when Postumus issued the Declaration of the Independence of Gaul, Spain, and Britannia from the Roman Empire, which would be known commonly as the Gallic Declaration of Independence. The document declared these lands to constitute the Roman Empire of Gaul, which would be informally called the Gallic Empire.

The reasons stated in the Declaration for the Gallic Empire's secession were largely based on a "Two Romes" theory that had become popular among the people, although never endorsed by Postumus up until this point. According to the Two Romes Theory, the Gallic Empire had emerged as an internally stable and increasingly prosperous New Rome; whereas the remainder of the Roman Empire's territory constituted the Old Rome, which was still tormented by civil war, barbarian invasions, and economic hardships. The Declaration cited various successes of Postumus, various generals and provincial governors, and the people; as well as various failures of the Emperors and institutions of the Old Rome. Also, the Declaration stated that the Gallic Empire owed the Old Rome and its Emperors nothing, that the war had proven that the Gallic Empire was sustainable, and that reunification of the Gallic Empire with the Old Rome would be harmful to territories belonging to the Gallic Empire and not particularly beneficial to the Old Rome.

276
The Gallic Empire could have been at peace in 276. The Roman invasion of Gaul was done, central authority in the Roman Empire was breaking down, and Italy was in ruins. Yet the Gallic Empire continued to be at war with the Roman Empire during 276.

The reason for the continuation of the war was the Gallic Empire's alliance with the Alamanni, Marcomanni, and Quadi. Although these three tribes enjoyed initial successes in their invasion of Noricum and Pannonia, Roman forces slowed them down; and by the middle of December 275, it was clear that the allied tribes were getting nowhere. Victorinus, who had remained in Raetia since he returned from Italy, asked Postumus to allow him to aid the Alammani by leading a campaign into Noricum. He received authorization from Postumus in early January. The invasion of Noricum began on January 9, 276. Thus, a new phase of the war began.

Victorinus' forces soon found themselves stalled in Noricum, so he asked Postumus for reinforcements. Postumus agreed to do so, even though this decision was poorly received by the people, the military, and the Senate. He also chose to personally lead the reinforcements, in an effort to boost their morale. The Gallic reinforcements began to move into Noricum on April 16. Thereafter, the Gallo-Germanic alliance steadily gained ground in Noricum.

Now after the sack of Rome, a republican government had emerged. As news of this development spread, republican factions came to power in other towns and cities that had been devastated during the Gallic invasion: some joined the new Roman Republic, while others chose to remain independent. For a while, Ascleiodotus and Probus ignored the republican states, but both chose to crush the republican movement after republican uprisings began occuring in areas that had been under their control.

Asclepiodotus and Probus easily overran the republican states during June 276. Unfortunately for both of them, their forces clashed several times. One such incident in the town of Lavinium (OTL Pomezia) the began on June 26 soon got out of hand, and resulted in a war between Asclepiodotus and Probus. By October, Probus gained the upper hand in this conflict. By November, Asclepiodotus realized he was going to lose northern Italy to Probus, so he fled Corsica. Then on November 25, Asclepiodotus was murdered, and Flavius Antiochianus took over the remainder of his realm. The conflict effectively had effectively ended by late December: Probus was firmly in control of northern Italy, and Antiochianus was not actively challenging him.

Gallo-Germanic gains in Noricum were slow but steady between May and November of 276. This was partially because Asclepiodotus could not send reinforcements to Noricum because he was contending with first the republics and then Probus. In October, however, Asclepiodotus had ordered all his forces in Noricum to move to Italy to fight Probus. Not all of the units complied, but enough of them did to make it possible for the alliance to make significant gains in November. The November Offensive ended when the allied armies reached the territory controlled by Pinianus.

277
After the alliance's momentum was stopped, it did not take long for Postumus to realize that he was now facing stronger armies than before. He also anticipated that Roman forces would be coming back toward Noricum soon, more numerous and less likely to be diverted than before. Also, he had maintained contact with Colonia Agrippina ever since he began his campaign, and he knew that both the Senate and the people were steadily losing patience with him. He had also been informed that Pinianus' forces had broken a long stalemate with the Quadi and retaken several towns during November. In other words, Postumus knew that his situation was fragile.

Postumus met with his generals and the leaders of the Alamanni, Marcomanni, and Quadi in late December 276. During this conference, he proposed that the alliance try to get the Suevi to join them. After several days of negotiations, all three Germanic tribes agreed to Postumus' proposal. Then in January 277, the Suevi leaders met with the allied leaders and agreed to enter the war after several days of talks.

Suevi forces did not actually arrive in Noricum until late March, however. Before then, Roman forces managed to retake parts of Noricum. The allied forces were able to reverse this counteroffensive within a month after the Suevi joined the war. The alliance reached the Arrabo River (OTL Rába River) by the end of April. For over five weeks thereafter, there was a stalemate.

A new front was opened up in early June. A large number of allied troops had been sent from Noricum, around Pannonia, to the area on the opposite side of the Danube from southeastern Pannonia. On June 9, the allied forces crossed the Danube, and proceeded to seize territory. Then a month later, allied forces on the west side of Pannonia broke through the Roman lines and began to take large swathes of Pannonia Superior.

During August, the generals and soldiers who had up until this point recognized Probus and Pinianus were beginning to lose faith in their respective leaders. In the Balkans, Lucius Flavius Aper rebelled against Pinianus. Probus' realm, a general stationed in northern Italy and then the governor of Africa Proconsularis defected to Antiochanus. Pinianus and Probus found themselves in conflicts with Aper and Antiochianus that were not quickly resolved, so they did not send the necessary reinforcements. This allowed the Gallo-Germanic alliance to continue to gain ground in Pannonia. Finally, the alliance took Sirmium (OTL Sremska Mitrovica) and Bassianae, the last two cities in Pannonia under Roman control, during October. Once both cities had fallen, the allies were in control of all Pannonia. On October 24, 277, in a speech before troops from each of the five parties in the alliance, Postumus declared that the alliance was victorious.

Return to Colonia Agrippina
The truth was that the war with the Roman Empire was not over, even though the Germanic tribes that the Gallic Empire had allied with had taken control of all of Pannonia and Noricum. It was probable that one or more factions in the Roman Empire would launch a campaign to retake Pannonia and Noricum, and also probable that such a campaign could happen very soon. In spite of this, Postumus wrote a letter to the Gallic Senate stating that the war had ended, that he intended to return to Colonia Agrippina in the near future, and that he intended to begin ordering the Gallic troops to return home.

Postumus himself crossed the Gallic border on December 30, 277 and triumphantly entered Colonia Agrippina on January 22, 278. Some Gallic soldiers began returning home at the same time, but they were only a minority. The majority of the Gallic forces would remain there for several years. In the letter Postumus wrote to the Senate before returning to the capital, he did say that "some" of the Gallic soldiers would have to stay in Pannonia and Noricum for an extended length of time. He had euphamistically written that the purpose of their continued presence would be to "assist our Germanic allies in consolidating their control over Pannonia and Noricum", which meant that the Gallic forces were to help the Germanic forces fight off any Roman campaign to retake the conquered area and put down any rebellion staged by the locals.

Post-War Gallo-Germanic Relations
After the war ended, the leaders of the allied tribes began trying to get their civilian populations to migrate to Pannonia and Noricum. The Alamanni were the first to start the migration process. Their leaders started summoning their civilians in September 277, a few weeks before the war ended. Quadi civilians began moving into northwestern Pannonia in November 277. The Suevi and Marcomanni civilians did not begin migrating until March 278.

Postumus maintained close contact with all four tribes after the war. He promised the Alamanni safe passage through Raetia. He also ordered Victorinus, who remained in Pannonia until 279, to provide the tribes with advice in setting up states in the conquered provinces. Postumus also encouraged the leaders of the allied tribes to form alliances with other Germanic tribes, because he anticipated that the political climate in Gaul would prevent him from being able to come to their aid again.

Postumus and Victorinus hoped that the Germanic settlers would create Roman-style political entities. This was not to be. The new orders in Pannonia and Noricum were heavily influenced by Germanic law. Alamannia and Quadium were essentially oligarchies. Suevia could hardly be called a state at all: it was really a confederation of independent subgroups of the Suevi tribe. Marcomannia was nominally a monarchy, but it was really a council that was in control of the new nation; and many subnational rulers gained considerable levels of autonomy. In Alamannia and Marcomannia, the Roman bureaucracy was largely left intact. In Quadium, it was modified. In many places in the Suevian Confederation, it was completely dissolved in favor of new administrative structures.

The Pannonian War and the Norican War
In December 278, a new war broke out in Pannonia. After the Gallic War for Independence had formally ended, the civil war in the Roman Empire continued. In the east, Pinianus had managed to prevail over Aper by July 278. He was now seeking to take Pannonia back. The majority of the Gallic soldiers who had gone to Pannonia during the previous war were still there; and they, the local Suevian army, and a few units from the other three tribes fought back against the Romans.

For several months, the allied forces in Pannonia were just enough to keep the Romans from getting anywhere. Then forces affiliated with Antiochianus invaded Alamannia in March 279. The Alamannian leaders sent a delegation to Colonia Agrippina, to ask Postumus to send troops back into Pannonia and Noricum. The Alamannian leaders knew that the Senate and people of Gaul would not tolerate another direct war with the Roman Empire, so they instructed their delegates to ask that the requested Gallic troops be deployed to the interior of Pannonia and Noricum to maintain order there, thereby freeing up Germanic soldiers to fight the Romans. Even this was unacceptable to the Senate. Postumus denied the Alamannian request and told the delegates that Alamannia and the other three Germanic states would have to fight off the Romans without any Gallic forces that were not already there.

The Pannonian War had ended by July 279. Pinianus had failed to retake any territory in Pannonia, and now he was facing another rebellion, this time from a general named Publius Aelius Aelianus. Thereafter, the allies sent additional troops to Alamannia to fight Antiochianus' forces, who had managed to make modest gains. For a couple of months, there was a stalemate. Then in September 279, the allies discovered a weakness in the Roman lines, broke through, and then began pushing Antiochianus' armies out of Alamannia. By December, all of Alamannia had been retaken.

Antiochianus began to lose support after his invasion of Alamannia failed. Some of his generals changed their allegience to Probus; while others began to rally behind a new candidate for the throne, a man named Lucius Valerius Messalla, the governor of Africa Proconsularis. Meanwhile, Pinianus, realizing his rule was coming to an end, peacefully surrendered to Aelianus in exchange for being allowed to retire. By 280, there were four major contenders for the Roman throne. All four made eliminating each other their first priority. No Roman faction would cause trouble for the Gallic Empire or its Germanic allies for many years.

Administrative Overhaul
In 278, Postumus spent several months formulating a significant modification of the Gallic administrative structure. He formally announced his reform plan to the Senate on August 13, 278, and the Senate ratified it on August 21.

The administrative reform had several features:
 * The province of Tarraconensis was to be split into six provinces, the eastern part of Lusitania was to be made into a new province called Vettonia, and the eastern half of Narbonensis was to become a new province called Massiliensis.
 * The relationship of the provincial governors to the military was to be modified. In the past, governors had been in charge of all military forces within their respective provinces. Hereafter, governors would retain control over a percentage of the forces within their respective provinces (such a percentage would vary by province and be determined by the Emperor), but many of the units in each province would be transferred to the command of a new type of official called a dux. The provinces would be grouped into military districts, with two or three provinces in each district; and within each military district, the dux would be responsible for the military forces over which the provincial governors did not retain command.
 * The classification of the majority of the provinces was to be changed from imperial to senatorial. The difference between the two classes of provinces was who appointed the governors: governors of imperial provinces were appointed by the Emperor, and governors of senatorial provinces were appointed by the Senate. When the Gallic Empire initially seceded from Roman rule, only Baetica and Narbonensis were senatorial; whereas now, only Germania Superior, Germania Inferior, Raetia, Massiliensis, Belgica, Transpadana, the Alpine provinces, Britannia Inferior, and three of the new provinces in northern Spain were to be imperial.
 * Changes were to be made to the civil service. In particular, the imperial postal service (which had been formed from the local branches of an identical Roman institution at the start of Postumus' reign) and the department dealing with correspondence between Colonia Agrippina and officials stationed elsewhere in the empire were to be enhanced.

Whereas the purpose of the earlier political reforms was to provide an alternative to armed rebellions against the Emperor, this new reform package was intended to make attempts by provincial governors to rebel more difficult. The partitioning of the larger provinces meant that the governors of the new provinces would have fewer troops under their command, and the introduction of the duces would further reduce the number of troops under the command of each governor. At the same time, the governors would retain some authority over the military forces in their respective provinces in order to prevent the duces from becoming too powerful. The civil service reforms were meant to ensure that the empire would be as integrated as possible. Postumus' reason for reclassifying the majority of the provinces stemmed from a belief that he had held for several years: that the Gallic Empire's future lay in a degree of cooperation between the Senate and the Emperor.

Another important event in the history of Gallic law came fourteen months later. In October of 279, Postumus asked several scholars to carry out a project of codifying all the laws of the Gallic Empire. Their task was not completed until after Postumus' death.

Death
Postumus designated Victorinus as his successor late in 278. Victorinus had proven himself to be a skilled general ever since Postumus began his rule. There were several other fine generals in the Gallic army: Postumus chose him mainly because of his role in the Gallic War for Independence.

Postumus' health began to deteriorate in early 279. In October, he recalled Victorinus to Colonia Agrippina to prepare him to take control of the empire. Victorinus arrived at the capital on January 11, 280. During the following months, Postumus heavily involved Victorinus in the administration of the empire.

On May 17, 280, Postumus tripped and fell after leaving a Senate meeting. He suffered a head injury as a result of that fall, and died on May 20, 280.

The Great Roman Civil War
Main article: Great Roman Civil War

The civil war that began in the Roman Empire in the summer of 276 continued long after the Gallic War for Independence, the Pannonian War, and the Norican War ended.

280 began with four generals fighting each other for control over what was left of the Roman Empire; namely Probus, Antiochianus, Aelianus, and Messalla. 280 ended with the elimination of Probus and Antiochianus from the war. Messalla gained control of all the territories that Antiochianus had ruled and most of those that Probus had ruled. Messalla's strategy was to use diplomacy to persuade generals and provincial governors to join him. Once Messalla had gained enough support, he launched an assult on the core of Antiochianus' realm. The campaign was successful, Antiochianus committed suicide, and Messalla took control of all of Antiochianus' territories in a matter of days. Less than two months thereafter, Probus was ousted and his regime was taken over by several of his generals, who agreed to side with Messalla.

During 281, Messalla fought to wrest control of the provinces of Dalmatia and Asia from Aelianus. For most of the year, he made little progress: by September, he had only managed to take control of a third of Dalmatia, the Dodecanese, and the area surrounding a small bay in Asia. In September, however, he sent more troops to Dalmatia, which enabled him to take over the majority of the province in a matter of weeks. At roughly the same time, Messalla's forces began to steadily gain ground in Asia.

Another development that took place in 281 was that the governor of Cappadocia, frustrated by the complete breakdown of central authority in the Roman Empire, refused to recognize any of the contenders for the purple. From Aelianus' point of view, the Cappadocia had seceded from the Roman Empire in everything but name. Aelianus launched a large invasion of Cappadocia, but Cappadocia managed to resist Aelianus.

The war finally ended in 282. During the spring, the governor of Lycia and Pamphylia abandoned Aelianus for Messalla. This enabled Messalla to win several important victories in Anatolia. This in turn prompted defections by several generals from Aelianus to Messalla. Meanwhile, Cappadocia was withstanding Aelianus' invasion fairly well, and the border province of Osroene began to rebel against Roman rule. All these events depleted Aelianus' remaining forces. Finally, on May 6, Messalla's forces won the Battle of Pergamon, which convinced all of Aelianus' remaining generals and provincial governors to recognize Messalla. Aelianus himself surrendered on May 30, thereby bringing an end to the war.

After the war ended, Aelianus spent two months under house arrest while Messalla figured out what to do with him. On August 6, Messalla met Aelianus in Thessalonica and presented him with a plan for sharing power. Messalla's plan, known as the Treaty of Thessalonica, nominally made Aelianus a secondary Emperor and gave him authority over most of Anatolia and the Balkans, but in reality was designed to make Aelianus Messalla's puppet. Aelianus signed the treaty because the only alternative was for him to be executed.

The Reign of Victorinus
On May 21, 280, the day after Postumus died, Victorinus addressed the Gallic Senate. He informed them that in accordance with Postumus' wishes, he would succeed Postumus as the new Gallic Emperor. The day after that, he announced his succession to the people. The funeral for Postumus was held the following day.

The Pannonia and Noricum Military Presence Scandal
There were over six thousand Gallic soldiers in Pannonia and Noricum immediately after the fall of Sirmium and Bassianae. By the time Victorinus became Emperor, over four thousand of them were still there. Even before he became Emperor, Victorinus knew he would face a dilemma over when to call those soldiers home. On the one hand, Victorinus knew that he could not keep those forces there indefinitely for political reasons; and it seemed that the Roman Empire would not pose a threat to the new states for years, as it was tearing itself apart. On the other hand, Victorinus recalled that the Roman Empire had attacked the emergent states even as the worst civil war in its history was taking place; and moreover, the new countries faced not only the threat of invasion by the Roman Empire or factions therewithin, but also rebellions on the part of the non-Germanic inhabitants of Pannonia and Noricum.

Victorinus wanted to maintain a military presence in Pannonia and Noricum as long as possible. In order to buy time, he decided to recall four hundred soldiers. He publicly announced these orders on July 22, 280. These soldiers began returning home in October 280. In fact, Victorinus had no intention of actually reducing the number of troops in Pannonia and Noricum: Victorinus encouraged local officials in the hometowns of the returning soldiers to hold extravegant homecoming ceremonies; and while the majority of the people's attention was directed toward those homecomings, Victorinus had his generals quietly deploy new soldiers to Pannonia and Noricum to replace the returning ones.

In January 281, it seemed that Victorinus' tactic had worked. All four hundred of the recalled soldiers had returned home, and all the replacements had been deployed. The commanders had managed to keep word from getting out that the replacement soldiers were bound for Pannonia and Noricum by first having them deployed a considerable distance from their hometowns, but still within Gallic territory, and then redeployed to Pannonia and Noricum. Victorinus did not perceive any more or less political pressure to completely withdraw from those areas than he had felt six months earlier. At the same time, it was common knowledge in the Gallic Empire that the western parts of the Roman Empire had united behind Messalla. At that point, it was unclear whether Messalla would win the eastern provinces as quickly as he had taken the western ones, and also if or when he would stage another invasion of the Germanic states. Thus, Victorinus believed he now had a convincing case for maintaining the military presence.

Exposure
Things went wrong for Victorinus during the summer and fall of 281, however. He decided to recall another four hundred soldiers who had been in the Germanic states for a long time and send eight hundred new soldiers, resulting in a net increase in the Gallic military presence.

The replacement forces had all arrived in Pannonia and Noricum by August. The locals soon realized that there were more Gallic soldiers in their countries than before. What Victorinus was not aware of was that the Gallic military presence had been becoming increasingly unpopular in all four of the Germanic states. The majority of the Germanic people believed that the Roman Empire had become too weak to pose a threat to them for a long time to come. The leadership was generally more supportive of the military presence; but several Suevian and Quadian nobles had openly suggested that half the Gallic forces should return home; and virtually none of the Germanic leaders believed that more Gallic troops were needed.

The net increase in the number of troops led to riots in several cities during September. The riots were quelled by the Gallic and local forces, and many people known or suspected to have been involved were arrested. The Gallic commanders were shocked to discover that the majority of the rioters were Germanic, rather than Latin. News of these developments trickled across the the Gallic border, in spite of efforts by generals to keep it a secret. Then in early September, the king of Marcomannia wrote a letter to Victorinus in which he said that he was displeased that more forces had been sent, noted that the arrival of the new forces had provoked riots, and called for a thousand of the Gallic soldiers to be recalled home without replacement within six months. He also wrote an identical letter to the Gallic Senate, as he knew that the Senate theoretically had the power to depose Victorinus, and considered the possibility that the Senate was unaware of what was happening.

Both letters reached Colonia Agrippina on November 12, 281. The Senate's copy fell into the hands of a senator who had been calling for a substantial reduction in the Gallic military presence in Pannonia and Noricum for over a year. The Senate's first meeting after the arrival of the letters took place on November 16, and Victorinus was present thereat. During the meeting, the senator who received the copy of the Marcomannian king's letter read the letter before the Senate, and an uproar immediately ensued. Victorinus was forced to admit that he had replaced all the soldiers who had come home during his rule, and had ordered a net increase in the number of soldiers stationed in Pannonia. Outrage was voiced by senators who had opposed the Gallo-Germanic alliance from the start, as well as those who wanted a partial or complete withdrawal. Even senators who did not object to the deployment of additional troops per se were upset the Victorinus had kept his actions a secret.

As soon as the meeting ended, the senators poured into the streets of Colonia Agrippina to tell the masses what they had learned. The people were outraged, and riots occurred near Victorinus' palace. As the news spread into the interior of the empire, unrest developed there as well. In many cities, including Colonia Agrippina, the army was able to put down the riots only with brutal force. At the same time, the Senate began debating whether to depose Victorinus, as well as possible replacements.

Resolution
By December 281, two senators and one general had emerged as potential candidates to replace Victorinus as emperor. Victorinus was spending much of his time trying to bargain with individual senators for their support. Most of the senators he spoke with demanded a withdrawal of at least a significant number of troops from Pannonia and Noricum. Then, on December 19, the Senate informed Victorinus that it intended to vote on whether to depose him if he did not recall at least two thousand soldiers from Pannonia and Noricum without replacement by March 1.

Victorinus spent the remainder of December sending out orders for several units to return home immediately. These orders reached Pannonia and Noricum a month later. The units began entering Gallic territory by late February. While these events were taking place, Victorinus appointed thirty people who were loyal to him to the Senate (increasing the size of the Senate from 200 to 230 senators), in order to make it harder for the Senate to depose him. At the same time, the strongest opponents of Victorinus united behind a single replacement candidate.

The Gallic Senate voted on whether to depose Victorinus on March 7, 282. Even though the Senate knew to expect the recalled army units to begin arriving in Gallic territory by that time, many senators were outraged that Victorinus had stuffed the Senate with his partisans, and some felt that he hould not have been given a chance to redeem himself in the first place. Victorinus only narrowly avoided deposition: the motion to depose and replace him failed by a vote of 109 to 121. The next day, five senators resigned in protest. Although the Senate chose not to depose Victorinus, it remained hostile to him for several months. That situation was resolved only in early 283, when Victorinus expelled fifty senators who had persistantly opposed his agenda and replaced them with reliable partisans.

Even though Victorinus was still emperor, he knew he had to honor the Senate's wish that he not replace the two thousand soldiers that were returning from Pannonia and Noricum. He did not recall any more troops for a while though. By this time, it was becoming increasingly likely that the Roman Empire would soon be united under Messalla. Even though the Roman army would definitely emerge from the civil war weaker than it was during the Pannonian and Norican Wars, Victorinus was concerned that it might still be strong enough to pose a threat to the Germanic states.

Formalization of the Monarchy
One thing that Victorinus inherited from Postumus was a project to codify all the laws of the Gallic Empire. This project was carried out by a seven-member committee. After Postumus died, Victorinus added five more men to the group. By June 282, the committee had completed its work, and they presented it to Victorinus on June 8. Victorinus was pleased with the codification, but at that point, he was planning to modify the structure of the Gallic state, so he told the committee that he could not ratify the legal code they had produced as it was. He then appointed himself to the committee to work with them on the revised product.

Throughout the imperial phase of Roman history thus far, the emperors had maintained a nominally republican form of government to justify their rule (although these republican vestiges had been gradually eroded over the course of three centuries). There had never been a formal office of Roman Emperor. Instead, every emperor held multiple civil and military offices simultaneously and assumed honorific titles. The Gallic Empire inherited this nominally republican system when it broke away from Rome. What Victorinus wished to do was eliminate most of the remaining trappings of a republic.

As Victorinus wished to portray himself as a benevolent ruler, he called the new monarchial office Princeps Civitatis (First Citizen). The offices of consul and Pontifex Maximus were to be abolished and their powers and duties consolidated in the new office. The offices of tribune and censor had become defunct in the Roman Empire long before the Gallic Empire seceded, although emperors continued to assume the powers that had previously been vested in those offices; and those powers were now to be officially granted to the emperor. The emperor also given ultimate authority over all the military forces in the empire, though such authority was delegated to the duces, provincial governors, and generals. The Senate would still exist, and it retained the authority to depose the emperor; but it was still largely a puppet of the emperor, as the emperor had absolute control over its membership.

Victorinus and the committee finished the revised legal codification in October 282. After Victorinus carried out his second round of stuffing the Senate with his allies, he proposed the codification to the Senate. The Senate ratified the codified laws on March 28, 283.

Religious Reforms
As emperor, Victorinus was the chief priest of the Gallic state religion. During the early 280s, Victorinus used this authority to inject Celtic themes into the state religion. One change he made was by promoting more frequent use of the Celtic names for deties worshipped by both the Gauls and Latinized people: for example, Mars was henceforward known as Letus, and Apollo became known as Grannus. Another change Victorinus made was injecting animistic themes into the state religion. Most other aspects of the state religion that were inherited from Rome were left unchanged.