The Danish Conquests of Anglia were a series of campaigns launched from Denmark at the Kingdom of England, and later at Anglia. Collectively they altered the course of English history, ensuring that the short lived England would henceforth be divided into Wessex and Anglia and that the Kings of Anglia would be firmly linked to the Estridsen dynasty of Denmark.
Viking adventurers had been drawn to the coastal settlements of Britannia and Eire for centuries. Britannia was one of the wealthiest lands in Europe and coupled with vulnerable monasteries on the coast it proved an irresistible lure to those in Scandinavia looking for riches and fame. Eventually this would lead to settlement as Norwegians took political control over Western Eire, the Wirral, Orkney and Jorvik whilst Danes menaced the southernmost kingdom of Wessex. Eventually defeated by Alfred and his successors they would settle down in a broad swath of Eastern England - the Danelaw. This area under Danish rule would be reconquered during the 910s by Edward the Elder whilst Jorvik and Northumbria would be nominally conquered by Aethelstan in 927 creating a united England for the first time.
Eirik Bloodaxe, ousted from the rapidly splintering Norway after his defeat at Haugar in 934, had fled to Jorvik with several powerful thralls. There he quickly eliminated his rivals and relaunched Jorvik as a separate entity with assistance from the Scots who had just suffered defeat at the hands of Aethelstan. Meanwhile to supplement his income he took to raiding the coast of the Danelaw, building a significant war-chest out of riches chiefly 'liberated' from the Danish Jarls. He probably had the intention of using the money to retake Norway but would not get the chance. After five years of bloody defiance Aethelstan crushed the combined forces of Eirik, Dublin and the Scots, although this was only achieved with significant help from the Danelaw. The Jarls extracted even more privileges out of the Wessex king and when Aethelstan died soon after, the north collapsed into chaos once more, strengthening their independence. Wessex would eventually pacify the north in the 950s but the Danelaw remained as independent as ever with more and more Danes settling.
A period of relative calm would give way to violence once more in the 980s. The Danish raiders were back. Aethelred II came under incessant pressure from the raiders leading up to the Battle of Maldon which was a crushing defeat for the English. A huge tribute was paid to the Danes for peace. Yet the raiding did not end and in 994 an even bigger horde of gold was paid to the foremost raider, Olaf II Tryggvason, who would use it to conquer Viken from Sweyn I Forkbeard. Aethelred II's rule was already shaky, he had only come to the throne thanks to the suspicious death of his half-brother Edward II and the endless taxation to pay for Danegeld did nothing to endear him to his lords. And now that Aethelred II's eagerness to pay was well-known the Danes came back in ever greater numbers. A lull in the raiding in 1000 allowed him some room for maneuver which would lead to the fateful decision to kill all Danes in England on 13th November 1002.
The First Conquests
Fearful that the Danes in his kingdom were disloyal, and planning to kill him, Aethelred II's ordering of the St. Brice's Day massacre would do far more damage than he could have dreamt of. Sweyn I Forkbeard's sister Gunhilde was among those killed while ruthless burning of Danes seeking refuge in a church in Oxford the shocked contemporaries. Sweyn I invaded in 1004 seeking vengeance and sacked Norwich. A further expedition in 1007 was bought off with more gold and the largest tribute of all was paid in 1012 to the army of Thorkell the Tall which spent three years harrying England.
With Thorkell entering the service of Aethelred, Sweyn I resumed the mantle of England's 'harrier-in-chief' and returned in 1013, this time out for conquest rather than money. By the winter Aethelred II had been forced to flee to Normandy where his wife Emma's brother Duke Robert II reigned. Sweyn was sworn in as king of England on Christmas Day by the cowed nobility. However he died in February 1014. Aethelred II was recalled and quickly began to move against Sweyn I's son, Cnut. Edmund II initially drove Cnut off and then defied his father by marrying one of his father's earls' widow, Ealdgyth. When Cnut returned in 1015 he made good headway into Northumbria but was stiffly resisted by Edmund. Aethelred died in April 1016 leaving Edmund in sole control of the English army. He would continue to clash with Cnut throughout the year until the Battle of Assandun on 18th October after which the Danes were victorious. The two generals negotiated a peace and divided the country.
Wessex & Anglia
Edmund took Wessex whilst Cnut took 'Anglia', in effect the Danelaw (including Danish Mercia), plus Jorvik and Northumbria. The agreement laid down was that in the event of either king's death the other's kingdom would revert to them.
Edmund avoided an assassination attempt in November 1016 and an exchange of hostages by both sides appeared to cement the division as well as prevent any further attempts to bump off the other. Cnut took to taxing his kingdom to a degree barely conceived of during Aethelred's time to reward his army while Edmund's half was in no fit state to raise any tax at all thanks to Aethelred II's lingering legacy, a situation which bred inertia in both kingdoms. Edmund's Wessex was in no fit state to reconquer Anglia whilst Cnut's Anglia seethed with turmoil until he carefully positioned close allies into newly created jarldoms beginning in 1018, spreading the old constitution of the Danelaw throughout the kingdom.
Cnut meanwhile married Aethelred's widow, Emma, forestalling any retaliation from Normandy and reconciling the English lords to his rule. In 1018 Cnut renounced his claims to the Wessexian throne and with relations soothed and internal divisions dampened was able to take an army and invade Denmark after the death of his eldest brother Harald II. Edmund's brother Eadwig campaigned alongside Cnut in Denmark and Pomerania. With his sons Sveinn I and Harthacnut installed as regents in Viken and Denmark Cnut returned to Anglia. Secure in his rule we would leave Anglia once more in 1027 to attend the coronation of Emperor Conrad II in Rome.
Edmund meanwhile set about establishing his power. Cnut's success in Scandinavia virtually removed the burden of viking raids, at least from the east. Instead he was faced with a resurgence of activity in the Manx Sea after Sigtrygg Silkbeard's victory over in Munster 1014. This kept him and his lords busy and led to an ill-fated attack on Dublin in 1028. Edmund was lucky to escape with his life after his forces were pinned down at Aughrim. He returned to Wessex to almost immediately face down a rebellion from his brother.
The division continued to hold after the deaths of both Edmund II and Cnut I in 1031 and 1032 respectively. The new kings of Wessex and Anglia, Edward III and Harald I had spent time together as children (during the high point of the hostage swapping) and were broadly supportive of the status quo. Harald was almost immediately threatened with invasion from his half-brother Harthacnut and Edward rallied to his defence, reasoning it was far better to have a friend on the Anglian throne than an unknown quantity. In addition Harthacnut was the son of Cnut and Emma of Normandy, and her two previous sons from Aethelred II were still in Normandy. Concern that Emma was actively engaged in trying to win one or perhaps both of the kingdoms for her children kept Edward and Harald united and a tentative force put together by Hardacnut was repulsed in 1036 whilst a more substantial invasion by Emma's other sons Edward and Alfred was defeated by an Wessex-Anglian army at London in 1041.
Relations seem to have broken down rapidly after London. As Harald attempted to gather a force to retake Denmark (which had been taken by Magnus I after the death of Harthacnut) he was constantly frustrated by revolt in Mercia and raids from Hordaland. Wessexian nobles were increasingly defiant of their sovereign and looked to potentially easy victories over the beleaguered Danes to increase their standing. Edward was forced to pay homage to Harald in 1049 after his brother Edmund was caught by Earl Godwin after sacking Coventry and killed trying to escape. Neither kings however could afford a decisive blow as both were still threatened by invasion from Normandy and Denmark.
Pressure on Anglia lessened after Harald's cousin Sweyn II Estridsson ousted Magnus I in 1047 and the death of Edward III in 1057 led to the minority of his son Edgar II. During the early part of Edgar's extraordinarily long reign Harald I would be succeeded by his son Aelfwine and then in turn by Sweyn II Aelfwinsson. Peace once more reigned between the two kingdoms. Wessex was busy projecting its power westwards into Cornwall and Wales and Anglia busied itself crushing repeated revolts, warring with Scotland and starting one of the most ambitious church building projects in Europe.
Relations were once again stable enough by 1096 so that Sweyn II could pawn Mercia to Wessex to raise the necessary capital to go on crusade. He would die of injuries and plague at Nicea in 1097. On hearing the news Edgar II took the chance to seize Mercia in full. Sweyn II had no surviving male heirs so his nobles took the dramatic step of electing one of their own, Harald II Godwinsson. A hugely experienced general he was nonetheless opposed by many of peers and so to prove his worthiness launched an attempt to retake Mercia with Frisian allies. This failed and Harald was rewarded with revolt.
The Second Conquest
Harald II's troubles had been carefully observed by his enemies in Denmark. Cnut IV saw him as an unlawful usurper and, with his own position in Denmark and Viken secure, launched an invasion of Anglia in 1098 before anyone else could beat him to it. Not only did he have the support of many nobles in Anglia, a vague hint of non-involvement from Wessex but he had also received a papal banner from Rome.
Landing in Norfolk in late September Cnut made good headway, sacking Norwich and Thetford while Harald was in Leicester. Harald's army was beaten at Elmham, Cambridge and Lincoln in quick succession in October. Harald himself fell at Lincoln. Crowned by the Bishop of Jorvik on Christmas Day Cnut IV (or II of Anglia) appeared to want to solve Anglia's issues as quickly as possible. By the end of January 1099 he had sent word to Edgar confirming Mercia as Wessex's and set his son Charles as regent, toured the earldoms receiving homage and confirming landholders with their rights, before returning to Denmark in August, where he would die in 1099.
Charles I was the ultimate beneficiary of the efforts of the Danish kings who had preceded him. The Anglia he inherited was hugely wealthy, well governed, free from invasion and more peaceful thanks to the loss of Mercia. A marriage to one of Sweyn II's daughters, Alftruda, ensured some semblance of continuation and good relations with his new lords. He maintained good relations with his uncles Niels I of Viken and Eric I of Denmark and an agreement in 1103 promised peace between the three kingdoms as long as an Estridsen reigned in all three. Meanwhile in Wessex Edgar II's seemingly unending reign resulted in nothing but repeated revolts from his own sons and grandsons who were outraged that he appeared unwilling to die and angry about the numbers of Norman lords taking important positions in the kingdom. Wessex-Anglian relations soured considerably during his reign but did not result in outright war, at least not until the late 1100s. By then the kingdoms were in a sense looking in different directions; Anglia toward the Low Countries and Denmark, Wessex to Francia and its Celtic neighbours.
Estridssen rule in Anglia was maintained until the mid-point of the War of Anglian Succession while a cadet branch ruled until 1610. Neither Anglia nor Wessex would ever have the resources or will to conquer the other and although they certainly would be at war many times over the centuries a general mood of acceptance of the division has always prevailed.