Æthelred II (c. 966 – 23 April 1016), known as the Unready, was King of the English from 978 to 1013 and again from 1014 until his death in 1016. His epithet does not derive from the modern word "unready", but rather from the Old English unræd meaning "poorly advised"; it is a pun on his name, which means "well advised".

Æthelred was the son of King Edgar and Queen Ælfthryth. He came to the throne at about the age of 12, following the assassination of his older half-brother, Edward the Martyr. His brother's murder was carried out by supporters of his own claim to the throne, although he was too young to have any personal involvement. The chief problem of Æthelred's reign was conflict with the Danes. After several decades of relative peace, Danish raids on English territory began again in earnest in the 980s.

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