Anglo-Saxon England or Early Medieval England, existing from the 5th to the 11th centuries from the end of Roman Britain until the Norman conquest in 1066, consisted of various Anglo-Saxon kingdoms until 927, when it was united as the Kingdom of England by King Æthelstan (r. 927–939). It became part of the short-lived North Sea Empire of Cnut the Great, a personal union between England, Denmark and Norway in the 11th century.