Æthelred, Lord of the Mercians

Æthelred became Lord of the Mercians in 879 following the disappearance of Mercia's last king, Ceolwulf II. His rule was limited to the western half of Mercia, as the eastern part was under Viking control. Æthelred's ancestry is unknown, and he likely led an unsuccessful invasion of Wales in 881. Shortly after, he acknowledged the lordship of King Alfred the Great of Wessex, solidifying this alliance by marrying Alfred's daughter, Æthelflæd.

In 886, King Alfred took control of London, which had been ravaged by Viking occupations, and entrusted it to Æthelred. London was traditionally a Mercian town. In 892, the Vikings renewed their attacks, and in 893, Æthelred led a combined force of Mercians, West Saxons, and Welsh to victory over a Viking army at the Battle of Buttington. He continued to fight alongside Alfred's son, Edward the Elder, for the next three years.

After 899, Æthelred's health may have declined, leading to Æthelflæd possibly becoming the effective ruler of Mercia. Æthelred's status is debated, with some sources referring to him as an ealdorman and others as Lord of the Mercians. He acted with considerable autonomy, issuing charters in his own name and maintaining Mercian independence until his death.

Æthelred died in 911 and was buried at St Oswald's Priory in Gloucester. After his death, his wife Æthelflæd succeeded him as Lady of the Mercians until her own death in 918.