Æthelred, lord of the Mercians (d. 911). ), king of Mercia, who was a benefactor of many churches in his several provinces and at last retired to a monastery.. He married Æthelflæd (c872-918) 886 JL in England, United Kingdom. He succeeded his brother Wulfhere in 675 and early on spent most of his time in warfare. Æthelred of Mercia was a main character in both The Saxon Stories novel series, and The Last Kingdom television series. In 676 he ravished Kent, taking Rochester.In 679, in a battle on the banks of the Trent, he defeated the Northumbrians, taking the province of Lindsey. Of unknown origins, by 883 Æthelred was in control of that western part of Mercia which had been left under Anglo-Saxon control when Vikings conquered the rest of the province. Æthelred was the lord of Mercia and the husband of Æthelflæd. Aethelred II of Mercia (857-911) was Lord of the Mercians from 881 to 911, succeeding Ceolwulf II of Mercia and preceding Aethelflaed.He was a weak ruler whose ambition of becoming "King of Mercia" was thwarted after a failed invasion of Wales in 881, after which he was forced to recognize King Alfred the Great of Wessex as his overlord. Æthelred, Lord of the Mercians (or Ealdorman Æthelred of Mercia) (died 911) became ruler of English Mercia shortly after the death of its last king, Ceolwulf II in 879. For others named Æthelred, see Æthelred of Wessexor Æthelred Mucel. Æthelred, Lord of Mercia was born 9999 in England, United Kingdom (Mercia) and died 911 inEngland, United Kingdom (Mercia) of unspecified causes. By 883, he had been replaced by Æthelred, Lord of the Mercians, who became ruler of Mercia with the support of Alfred the Great, king of Wessex.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 (or Ealdorman Æthelred of Mercia; died 911) became ruler of English Mercia shortly after the death of its last king, Ceolwulf II in 879. Aethelred, (died 716, Bardney, Eng. Æthelred… Source for information on Æthelred, lord of the Mercians: The Oxford Companion to British History dictionary. His rule was confined to the western half, as eastern Mercia was then part of the Viking-ruled Danelaw.