Æthelred of Mercia

Æthelred
Stained glass window in St John's Chester
King of Mercia
Reign	675–704
Predecessor	Wulfhere
Successor	Coenred
Born	c. 645 AD
Died	c. 709 AD
Burial	Bardney Abbey, Lindsey
Spouse	Osthryth
Issue	Ceolred Ceolwald (possibly)
Dynasty	Iclingas
Father	Penda
Mother	Cynewise (possibly)
Religion	Roman Catholic

Æthelred (/ˈæθəlrɛd/; died after 704) was King of Mercia from 675 until 704. He was the son of Penda of Mercia and came to the throne in 675, when his brother, Wulfhere of Mercia, died. Within a year of his accession he invaded Kent, where his armies destroyed the city of Rochester. In 679 he defeated his brother-in-law, Ecgfrith of Northumbria, at the Battle of the Trent: the battle was a major setback for the Northumbrians, and effectively ended their military involvement in English affairs south of the Humber. It also permanently returned the kingdom of Lindsey to Mercia's possession. However, Æthelred was unable to re-establish his predecessors' domination of southern Britain.

He was known as a pious and devout Christian king, and he made many grants of land to the church. It was during his reign that Theodore, the Archbishop of Canterbury, reorganized the church's diocesan structure, creating several new sees in Mercia and Northumbria. Æthelred befriended Bishop Wilfrid of York when Wilfrid was expelled from his see in Northumbria; Æthelred made Wilfrid Bishop of the Middle Angles during his exile and supported him at the synod of Austerfield in about 702, when Wilfrid argued his case for the return of the ecclesiastical lands he had been deprived of in Northumbria.

Æthelred's wife, Osthryth, was a daughter of King Oswiu, one of the dominant 7th-century Northumbrian kings. Osthryth was murdered in unknown circumstances in 697, and in 704 Æthelred abdicated, leaving the throne to Wulfhere's son Coenred. Æthelred became a monk at Bardney, a monastery which he had founded with his wife, and was buried there. Ceolred, who was Æthelred's son (though apparently not by Osthryth), became king after Coenred; it is also possible that Æthelred had another son named Ceolwald who was briefly king before Ceolred.