By Marcus Wells - History Student @ St Peter's College, Oxford
In 716, Aethelbald became King of Mercia, inheriting overlordship of Middlesex, Surrey and the Hwicce. Expansion under himself and his successors, Offa and Cenwulf, resulted in Mercia gaining overlordship over Sussex, Kent, East Anglia and, to a varying extent, Wessex. This political hegemony has been referred to as the ‘Mercian Supremacy’, and allowed the three rulers of the period to achieve real change in Southumbrian Britain. The economic effects of this included wider trade, both domestic and foreign.