Edmund Ironside succeeds his father Æthelred the Unready as king of England.
Edmund Ironside (c. 990 – 30 November 1016; Old English: Ēadmund, Latin: Edmundus; sometimes also known as Edmund II) was King of the English from 23 April to 30 November 1016. He was the son of King Æthelred the Unready and his first wife, Ælfgifu of York. Edmund's reign was marred by a war he had inherited from his father; his cognomen "Ironside" was given to him "because of his valour" in resisting the Danish invasion led by Cnut the Great.Edmund was not expected to be King of England; however, by June 1014 two elder brothers had died, making him heir apparent. At the end of the same year, England was conquered by Sweyn Forkbeard, who died shortly thereafter. Æthelred was able to reclaim the throne, despite opposition. Sweyn's son, Cnut, was defeated and returned to Denmark, where he assembled an invasion force to re-conquer England. It would not arrive for another year.
After regaining the throne, the royal family set about strengthening its hold on the country with the assistance of Eadric Streona (Edmund's brother-in-law). People who had sided with the Danes in 1014 were punished, and some were killed. In one case, two brothers, Morcar and Sigeferth, were killed and their possessions were taken by Æthelred. Sigeferth's widow Ealdgyth was imprisoned within a monastery, but she had already captured Edmund's attention. Cnut returned to England in August 1015. Over the next few months, Cnut pillaged most of England. Edmund joined Æthelred to defend London, but in 1016 Edmund unofficially named himself the Earl of the East Midlands and raised a revolt against his father. Without the king's permission he took Ealdgyth from the monastery, and married her; it would have been a politically advantageous marriage, since she was a member of one of the strongest families in the Midlands.
Æthelred died on 23 April 1016, making Edmund king. It was not until the summer of 1016 that any serious fighting was done: Edmund fought five battles against the Danes, ending in his defeat on 18 October at the Battle of Assandun, after which they agreed to divide the kingdom, Edmund taking Wessex and Cnut the rest of the country. Edmund died shortly afterwards on 30 November, leaving two sons, Edward and Edmund; however, Cnut became the king of all England, and exiled the remaining members of Edmund's family.