Mercia, kingdom of. Mercia dominated Anglo-Saxon politics in the late 7th and 8th cents. The name ‘Mercians’ means ‘the borderers’ and is thought to derive from their position between the Anglo-Saxon settlements of the east coast and British kingdoms of the west. The middle Trent valley was the heartland of the Mercian kingdom, which included the modern counties of Staffordshire, Leicestershire, Nottinghamshire, southern Derbyshire, and north Warwickshire. Within this area lay the Mercian episcopal centre of Lichfield (founded 669 and briefly an archbishopric during the reign of Offa) and the important royal centres of Repton and Tamworth. The Tribal Hidage, which may be a Mercian tribute-list of the late 7th cent. appears to show this core area surrounded by other provinces, including those of the Pecsaete (Peak District) and Lindsey to the north, the Wreocensaete (Wrekin) and Hwicce to the west, and numerous small peoples of the Middle Angles to the south and east.

The first Mercian king who is reliably attested is Cearl, whose daughter Cwenburh married Edwin of Deira in the early 7th cent., but it is not known how or whether he was related to any subsequent Mercian kings. It is usually assumed that it was Penda (c.626–55) who established Mercia as a major Anglo-Saxon kingdom. He and his son Wulfhere (658–75) followed an aggressive policy which enabled them to collect tribute from the southern Anglo-Saxon kingdoms, Northumbria, and probably some British kingdoms as well. Rivalry with Northumbria was intense for much of the 7th cent. and led to the deaths of several kings of both nations in battles, including those of Heathfield, Winwaed, and Trent, as well as by more underhand means. But although military force was the basis of their power, Penda and Wulfhere also established relationships with kings of other provinces, including those of the Hwicce, South Saxons, and East Saxons.

The 8th cent. was dominated by two very powerful kings Æthelbald (716–57) and Offa (757–96), both of whom claimed descent from Penda's brother Eowa. During their reigns many of the peripheral midland peoples were absorbed into Mercia and they attempted to extend Mercian control, as opposed to mere tribute-collecting overlordship, to eastern parts of Wales, East Anglia, and provinces south of the Thames. Kent and Sussex became Mercian provinces and their native rulers were deposed. Wessex remained independent, but lost territory south of the rivers Thames and Avon to Mercia. Unfortunately we have few written records produced in Mercia itself from this period, but surviving remains which reflect the wealth and power of the 8th-cent. Mercian kings include Offa's Dike and the churches of Brixworth and Repton. The extended boundaries of Mercia were maintained by Cenwulf (796–821), but increasing discontent with Mercian dominance in Kent, East Anglia, and Wessex and rivalry within Mercia between different collateral lines weakened Mercian hegemony. When Egbert of Wessex defeated Beornwulf of Mercia at the battle of Ellendun in 825 he was able to permanently detach Kent, Sussex, Surrey, and the East Saxons from Mercian control. The only Mercian possession south of the Thames was Berkshire which seems to have been ceded to the West Saxons by Burgred (852–74).

However, West Saxon successes did not really threaten the main Mercian province. It was the ‘great Danish army’ led by the sons of Ragnar Lothbrok which shattered the kingdom in 874. Burgred was expelled, but Ceolwulf II (874–9) was allowed to rule in western Mercia (centred on the former Hwiccian province). The area became increasingly dependent on Wessex for survival and Æthelfleda of Wessex, a daughter of Alfred who had married Ceolwulf's successor Æthelred, was ruler of the province in the early 10th cent. When Æthelfleda died in 918, her brother Edward the Elder, who was already winning parts of eastern Mercia from Viking control, annexed western Mercia as well. Although the Mercians continued to have some distinctive identity and in 957–9 had Edgar as their own subking, for most practical purposes they were controlled through ealdormanries and shires as part of the kingdom of England. Although most Mercian shires are mentioned for the first time in 10th-cent. records, it is likely that their boundaries were influenced by earlier Mercian administrative arrangements, many of which in turn depended upon the bounds of once independent peoples who had been integrated into the Mercian province.

Barbara Yorke