this period, however, and in 825 Egbert defeated the Mercian king Beornwulf (who had overthrown Ceolwulf in 823) at Ellendun. The Battle of Ellendun proved decisive. At this point, Mercia lost control of Kent, Sussex, Surrey, and possibly also Essex. Beornwulf was slain while suppressing a revolt amongst the East Angles, and his successor, a former ealdorman named Ludeca (reigned 826–827), met the same fate. Another ealdorman, Wiglaf, subsequently ruled for less than two years before Egbert of Wessex drove him out of Mercia. In 830 Wiglaf regained independence for Mercia, but by this time Wessex had clearly become the dominant power in England. Circa 840 Beorhtwulf succeeded Wiglaf. Arrival of the Danes In 852, Burgred came to the throne, and with Ethelwulf of Wessex subjugated North Wales. In 868 Danish invaders occupied Nottingham. The Danes drove Burgred from his kingdom in 874 and Ceolwulf II took his place. In 877 the Danes seized the eastern part of Mercia, which became part of the Danelaw. Ceolwulf, the last king of Mercia, left with the western half, reigned until 879. From about 883 until his death in 911 Æthelred, Lord of the Mercians, ruled Mercia under the overlordship of Wessex. Alfred changed his title from 'king of the West Saxons' to 'king of the Anglo-Saxons' to reflect the acceptance of his overlordship of all southern England not under Danish rule. All coins struck in Mercia after the disappearance of Ceolwulf in were in the name of the West Saxon king. Æthelred had married Æthelflæd ( 870 – 12 June 918), daughter of Alfred the Great of Wessex (), and she assumed power when her husband became ill at some time in the last ten years of his life. After Æthelred's death in 911 Æthelflæd ruled as "Lady of the Mercians", but Alfred's successor as King of the Anglo-Saxons, Edward the Elder (), took control of London and Oxford, which Alfred had placed under Æthelred's control. Æthelflæd and her brother continued Alfred's policy of building fortified burhs, and by 918 they had conquered the southern Danelaw in East Anglia and Danish Mercia. Loss of independence When Æthelflæd died in 918, Ælfwynn, her daughter by Æthelred, succeeded as "Second Lady of the Mercians", but within six months Edward had deprived her of all authority in Mercia and taken her to Wessex. Edward was succeeded as king of the Anglo-Saxons by his eldest son