The Danish conquests had destroyed the kingdoms of Northumbria and East Anglia and divided Mercia in half, with the Danes settling in the north-east while the south-west was left to the English king Ceolwulf, allegedly a Danish puppet. When Ceolwulf's rule came to an end he was succeeded as ruler of "English Mercia" not by another king but by a mere ealdorman, Aethelred, who acknowledged Alfred's overlordship and married his daughter Ethelfleda. The process by which this transformation of the status of Mercia took place is unknown, but it left Alfred as the only remaining English king.