r. 757-796 Anglo-Saxon King Ruler of Mercia, a kingdom in England, Offa left behind what is undoubtedly the third most well-known structure of pre-Norman Britain, after Stonehenge and Hadrian's Wall. Like the latter, Offa's Dyke is a line...

Offa (died July 26/29, 796) was the King of Mercia from 757 until his death. Prior to the rise of Wessex in the 9th century, he was arguably the most powerful and successful of the Anglo-Saxon kings, effectively ruling much of Britain south of the River...