The Mercia were a large and powerful tribe of Anglo-Saxon Britons ruling the English Midlands from Wales in the west, East Anglia in the east, the River Humber in the north and the River Thames in the south, and the less powerful tribes that lived in those parts. Suffering from Viking attacks during the 9th century, the kingdom was divided between Britons and Danes until during the 10th century Edward the Elder conquered the Danishlands and the area was ruled by earldormen on behalf of the Wessex Kings, who ruled all England. Research Mercia