Ceolwulf II was the last king of independent Mercia. He succeeded Burgred of Mercia who was deposed by the Vikings in 874. His reign is generally dated 874 to 879 based on a Mercian regnal list which gives him a reign of five years. However, D. P. Kirby argues that he probably reigned into the early 880s. By 883, he was replaced by Æthelred, Lord of the Mercians, who became ruler of Mercia with the support of Alfred the Great, king of Wessex.

Æthelred, Lord of the Mercians became ruler of English Mercia shortly after the death or disappearance of its last king, Ceolwulf II in 879. Æthelred's rule was confined to the western half, as eastern Mercia was then part of the Viking-ruled Danelaw. His ancestry is unknown. He was probably the leader of an unsuccessful Mercian invasion of Wales in 881, and soon afterwards he acknowledged the lordship of King Alfred the Great of Wessex. This alliance was cemented by the marriage of Æthelred to Alfred's daughter Æthelflæd.