He began his reign by ravaging the Britons, probably as an act of vengeance, but his name is also included among a group of northern and western kings said to have made submission to the Anglo-Saxon king Edgar in 973, perhaps at Chester; and the chronicler Roger of Wendover (Flores Historiarum, under the year 975) states that shortly afterward Kenneth received from Edgar all the land called Lothian (i.e., between the Tweed and the Forth rivers). This is the first mention of the River Tweed as the recognized border between England and Scotland. Kenneth was slain, apparently by his own subjects, at Fettercairn in the Mearns.