A gold dinar, inscribed with the name of King Offa of Mercia.
Gold dinar of Offa of Mercia (British Museum, CM 1913,1213.1)


Offa was one the most powerful kings in the British Isles in the eighth century.

Offa’s rise to power

Offa made his first appearance when he became king of Mercia in 757. He was one of several men who vied for the throne after the death of his distant relative, King Æthelbald (reigned 716–757). 

Like many rulers before him, Offa had ambitions to expand his power over the other Anglo-Saxon kingdoms. Unlike his predecessors, he deposed and demoted kings in the territories he conquered, rather than letting them rule as sub-kings.

Offa expanded his power over the wealthy kingdom of Kent. He faced resistance from Kentish nobles throughout his reign, but thereafter Kent never had an independent ruler again. Offa also weakened the authority of the archbishop of Canterbury by persuading the pope to establish another archbishopric at Lichfield, in the heartland of Mercia. 

Offa extended his power further by arranging for his daughters to marry the kings of other Anglo-Saxon kingdoms, including Northumbria and Wessex. He even offered both a son and a daughter in marriage to the children of the emperor Charlemagne (reigned 768–814). Charlemagne does not seems to have taken kindly to that proposal, as for a period, both he and Offa placed an embargo on trade with one another.

Few narrative sources survive for Offa’s reign, and so historians have used charters, letters, genealogies and archaeological finds to piece together these events.

Offa’s legacy

Although Offa was extremely powerful, much of his work was undone after his death. He had intended that his son, Ecgfrith, should succeed him, but Ecgfrith was killed within a year of Offa’s death. The archbishopric at Lichfield was also abolished by 803. 

Offa himself was remembered as an impressive leader. A century after his death, he was described by Asser, King Alfred’s biographer , as a ‘vigorous king … who terrified all the neighbouring kings and provinces around him, and who had a great dyke built between Wales and Mercia from sea to sea’ (translated by M. Lapidge and S. Keynes, Alfred the Great, Harmondsworth, 1983, p. 71).

A sword said to have been owned by Offa was one of the most prized possessions of Atheling Æthelstan, the eldest son of King Æthelred the Unready , who died in 1014; and one of the three giant Bibles made at Wearmouth-Jarrow before 716 was also reputedly owned by King Offa. 

Offa’s legacy is also commemorated in Offa’s Dyke, which still runs along part of the border between England and Wales. 

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