In 1015, after returning to Denmark, Cnut asked his brother Harald, who had assumed the Danish throne in Cnut’s absence, to divide Denmark between them. Furthermore Cnut was planning on conquering England again, giving his brother an eventual choice of Denmark or England if he would help in his campaign, but Harald refused, and Cnut went alone.
Æthelred had fallen ill, and his son Edmund Ironside was in a violent dispute with Eadric Streona, the powerful ealderman of Mercia, who joined forces with Cnut to conquer the throne of England. When Æthelred died on 23 April 1016, Edmund was elected king by the chief men in London. Cnut failed in his assault of London, and he divided his forces to fight Edmund in Essex at Penselwood, Somerset and Sherston, Wiltshire. Cnut’s last forces were ultimately driven out of London and defeated after crossing the Thames at Brentford. Eager to succeed, Cnut tried another siege in Essex, but was again unsuccessful; Edmund drove Cnut into Kent, where Eadric Streona abandoned his campaign.
Medieval impression depicting Edmund Ironside (left) and Cnut the Great in battle.
Edmund overtook Cnut and his army at the hill of "Assandun" (it is uncertain whether this is Ashingdon or Ashdon, Essex), but lost the ensuing battle. Cnut and Edmund finally met in Gloucestershire where they agreed to divide the kingdom: Edmund took Wessex and Cnut Mercia and Northumbria and was promised a payment to his army. London, which had been able to stand its ground during the earlier attempts to overtake it, also came to terms with this deal and accepted the Danes' presence in England. When Edmund died soon after, on 30 November, Cnut succeeded to the entire kingdom.
The events during the following years are obscure, but he seems to have travelled back and forth between Denmark and England a few times; he stayed in Denmark over the winter of 1019 and 1020 and went to Denmark again for a short while in the first half of 1023.
In 1027 Cnut went on pilgrimage to Rome. In a letter from the same year, he gives an account of how he was received by Pope John XIX and the new Roman emperor Conrad II (whose coronation Cnut was present at). He is thought to have negotiated with the pope, achieving better conditions regarding taxation for the church in England and its archbishops.
From Rome Cnut is believed to have travelled to Denmark yet again. When he returned to England, he gathered his troops and set off for Norway in 1028, determined to destroy King Olaf Haraldsson and claim the throne for himself. King Olaf was at this time deserted by many of his followers, and was driven into exile, forced to give up the throne. Shortly after Cnut returned to England in 1029, he sent his consort Ælfgifu of Northampton to rule in his place along with their son Swein. Olaf did come back to fight for the throne, but was ultimately defeated and killed on 29 July 1030 in the Battle of Stiklestad.
Thus became Cnut "king of all England, and Denmark and the Norwegians and of some of the Swedes" as is written in a twelfth-century copy of one of Cnut’s letters. What parts of Sweden he ruled and when is disputed.
The last Danegeld
One of the most prominent features of Cnut’s reign in England is the last Danegeld he collected from the English in 1018. £72,000 was paid to Cnut and his men by the English, and £10,500 was paid by the Londoners. If these figures are true to reality, it was an extremely high level of taxation, making it possible for Cnut to pay off the men in his army, most of who returned to Denmark.
Relationship with the English church
As King of the English, Cnut maintained a good relationship with the English church. Since church records are among the best kept through history, there are several accounts of gifts and generosities given by Cnut to various churches throughout England, e.g. this illustration from the New Minster Liber Vitae of Cnut and his wife Emma of Normandy presenting a large gold cross to the New Minster in Winchester – later known as Hyde Abbey.
Cnut's relationship to the church was more than a merely religious matter. There was a tendency to stress the Christ-like attributes of the ruling king in order to sharply distinguish him from the people he ruled; something not easily done without acknowledgment from the church. This must have been important for Cnut both whilst ruling, and for the sake of ensuring the church’s acceptance of his successor. One of the ways of doing this, was to keep close control over the church’s appointment of archbishops and the like, making sure the most important sees of church were held by people in favour of Cnut’s kingship, thus tying church and politics closely together.