An authoritative biography of Offa of Mercia, revealing his importance as the king who stood at the turning point of Anglo-Saxon history Offa ruled the Mercian heartland of the west midlands from 757 to 796. But while Alfred the Great and his dynasty are seen as agents of a new beginning that resulted in a unified Anglo-Saxon kingdom, Offa is best remembered as the builder of a great dyke and as a symbol of an older, divided order. In this major new biography, Rory Naismith challenges this view. Naismith reveals how Offa cemented Mercia's position as the dominant force in the southern part of Britain, strengthened the internal cohesion of his domains, and laid the basis for a new model of kingship. Drawing on a wide range of sources, including charters, coins, and chronicles, Naismith reveals Offa as a king who was ambitious and successful, and who carefully constructed his image and that of the royal family. Far from just one in a sequence of overlords, Offa had a lasting impact on how kingship was practised and conceived across England.