In England in the eighth century, in the midst of the so-called Dark Ages, Offa ruled Mercia, one of the strongest Anglo-Saxon kingdoms. For over 30 years he was the dominant warlord in the territory south of the Humber and the driving force behind the expansion of Mercia’s power. During that turbulent period he commanded Mercian armies in their struggle against the neighboring kingdoms of Northumbria and Wessex and against the Welsh tribes.