Mercian Supremacy

The Mercian Supremacy is a term commonly used to describe that period of English history between AD 600 and 900,^[1] in which the Kingdom of Mercia dominated the Anglo-Saxon Heptarchy. The term appears to have been coined by Frank Stenton, who put forward the argument that the unification of England south of the Humber under Mercia had been achieved during the reign of King Offa^[2], although opinion on the relationship between Wessex and Mercia at this time remains divided.

While the precise period covered remains uncertain (depending upon whether the reigns of King Penda and Wulfhere are included or not), the end of the era is generally agreed to be around 825, following the defeat of King Beornwulf at the Battle of Ellandun, near Swindon.

Nicholas Brooks noted that "The Mercians stand out as by far the most successful of the various early Anglo-Saxon peoples until the later ninth century", and with the exception of 3 years under Northumbrian domination, this is certainly the case between 633 and 825^[3].

Recorded by Bede as the nemesis of early Anglo-Saxon Northumbria, King Penda was responsible for the early expansion of Mercian territory, but his reign ended with defeat followed by a brief three-year period of Northumbrian rule. The rebellion against Northumbria by Penda’s son Wulfhere in 658 was quickly followed by the restoration of Penda’s kingdom and then by a period of expansion which saw the influence of Mercia reach as far south as the Isle of Wight. This period of expansion was briefly hindered by the loss of Lindsey between 661 and 665, but its recapture by Æthelred following the Battle of the Trent in 679 secured Mercia’s position as the dominant power for more than a century.

Mercia’s grip on Essex, Sussex and Kent seems to have been tenuous until 716, when Æthelbald restored Mercia’s control for over 40 years. The rise of Offa as king in 757 created a golden age for Anglo-Saxon Mercia. Some suggested that it is Offa’s defeat of the Welsh and the West Saxons of Wessex that established the Mercian supremacy, which remained unchallenged until 825 when Ecgberht, king of Wessex supported an East Anglian rebellion against Beornwulf of Mercia, whose death at Ellandun effectively brought the Supremacy to an end.

References

1. ^ Webster, L., and J. Backhouse (1991). "The Mercian Supremacy". In L. Webster and J. Backhouse. The Making of England, Anglo-Saxon Art and Culture, AD 600-900. London. pp. 193–253. 
2. ^ Stenton, F. M. (1970). "The Supremacy of the Mercian kings". In D. M. Stenton. Preparatory to Anglo-Saxon England. Oxford. pp. 48–66. 
3. ^ *Brooks, N. (1989). "The formation of the Mercian kingdom". In Steven Bassett. The Origins of Anglo-Saxon Kingdoms. Leicester.  p.159