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.

Osthryth was murdered in unknown circumstances in 697, and in 704 Æthelred abdicated, leaving the throne to Wulfhere's son Coenred.

[1] The earliest Mercian king about whom definite historical information has survived is Penda of Mercia, Æthelred's father.

[3] The fifth of these was Edwin of Northumbria, who was killed at the battle of Hatfield Chase by a combined force including Cadwallon, a British king of Gwynedd, and Penda.

Within a year Oswald, Edwin's nephew, killed Cadwallon and reunited the kingdoms, subsequently re-establishing Northumbrian hegemony over the south of England.

[8] By the early 670s, Wulfhere had become the most powerful king in southern Britain, with an effective hegemony over all the Anglo-Saxon kingdoms except for Northumbria.

Despite its focus on the history of the church, this work also provides valuable information about the early Anglo-Saxon kingdoms.

For Wessex and Kent, Bede had informants who supplied him with details of the church's history in each province, but he appears to have had no such contact in Mercia, about which he is less well-informed.

[18] In 674, according to Stephen of Ripon, Wulfhere "stirred up all the southern nations against [Northumbria]",[19] but he was defeated by Oswiu's son Ecgfrith who forced him to surrender Lindsey, and to pay tribute.

[24] The reason for his attack is not recorded, but he may have wished to prevent King Hlothhere of Kent from regaining control of Surrey, which had been recently brought into the Mercian orbit by Wulfhere.

[26] A third suggestion is that the kings of Essex solicited the invasion, in response to recent Kentish attempts to gain dominance over the East Saxons.

[24][28] Early in Æthelred's reign, Theodore, the Archbishop of Canterbury, began a substantial reorganization of the church in Mercia.

[29] Æthelred was a devout king, "more famed for his pious disposition than his skill in war",[30] and he made several gifts of land to the expanding church, including grants at Tetbury, Long Newnton, and Somerford Keynes.

As a result, peace was restored between the kings and peoples, and in lieu of further bloodshed the customary compensation was paid to King Ecgfrith for his brother's death.Æthelred took possession of Lindsey again after the battle; the change in control this time was lasting, and Lindsey remained part of Mercia until the Viking invasion of the 9th century remade the map of England.

Cædwalla had successfully conquered the kingdoms of Sussex and Kent, and his abdication may have contributed to the unsettled history of the southeast over the next few years.

[39][47] Alternatively, Æthelred may have needed assistance in Kent from the East Saxons who may have been independent of Mercia for a decade or more by that time.

[48][49][50] The latter charter also appears to show that a comes, or local official, was put in place by the Mercians to protect their interests.

[39] The increasing strength of the West Saxons under Cædwalla and Ine would have limited Mercian opportunities in that direction.

[22] The Northumbrians were no longer a distraction; they had been contained north of the Humber since the Battle of the Trent, and became even less of a threat after their disastrous defeat in 685 at the hands of the Picts.

Hence Osthryth's murder may have been in revenge for Peada's assassination,[39] though it has also been interpreted more directly as a sign of continuing hostility between Northumbria and Mercia.