Æthelred II c.968 – 23 April 1016), known as Æthelred the Unready, was King of the English from March 978 to December 1013 and again from February 1014 until his death in April 1016. He was the son of King Edgar (reigned 959–975) and Queen Ælfthryth. Æthelred came to the throne after the assassination of his older half-brother, King Edward the Martyr, a crime which deeply shocked people. The epithet "Unready" is a pun on his name in Old English, Æthel (noble) and ræd (counsel).
Shortly after Æthelred's accession Viking attacks resumed after a generation of peace. Minor raids in the 980s escalated to large scale attacks from the 990s, and as the English were rarely victorious in battle the king and his advisers resorted to giving the Vikings tribute to leave England, payments which are often (incorrectly) called Danegeld. In the 1000s increasingly destructive raids by Viking armies wore down English resistance, and in December 1013 King Swein Forkbeard of Denmark conquered England. Æthelred fled to Normandy, but when Swein died in February 1014 he was able to return to the throne and drive out Swein's son Cnut. In early 1015 civil war broke out when Æthelred's favourite Eadric Streona murdered close allies of Æthelred's oldest surviving son, Edmund Ironside. Cnut returned soon afterwards and Edmund and Æthelred tried to unite against him, but they were hampered by suspicion between them, Eadric's treachery and Æthelred's poor health. He died in April 1016 and Edmund carried on the war until he died in December 1016 and Cnut became king of all England.