The term OFFA, KINGDOM OF is related to the Anglo-Saxon kingdom of Mercia. Mercia was an independent kingdom located in what is now the English Midlands from the 6th century until it was absorbed into the Kingdom of England in the 10th century. It was ruled by the powerful Offa, who reigned from 757 to 796. During his reign, Offa was able to expand the kingdom's borders and establish a strong central government. He also constructed a defensive earthwork known as Offa's Dyke, which marked the boundary between Mercia and Wales.