Athelred II (13 March 968 — 23 April 1016) nicknamed the Unready was the King of England twice. The first time was from 978 until in 1013 where a Viking king, Sweyn I of Denmark, overthrew him. The second time was from Sweyn's death in 1014 until Athelred's death in 1016. He was the son of Edgar and his second wife, Ælfthryth. He succeded his older half-brother, Edward II, in 978 when Athelred was only ten years old. During his reign where he had to fight against Viking invaders in England.