Possibly a historical early Irish chieftain, frequently cited as the ultimate ancestor in medieval genealogies. Both Labraid Loingsech of Leinster and Conn Cétchathach [of the Hundred Battles] claimed descent from him. In stories composed hundreds of years after he would have lived, Úgaine is described as a foster-son of Queen Macha who ruled at Tara for forty years, extending his dominion over Scotland, the Isle of Wight, and eventually over all of Europe. A story known in the 10th century, now lost, has Úgaine campaigning in Italy. He is described as marrying Cesair (2), a ‘daughter of the king of the Franks’, who bore him twenty-five children. This Cesair (or Cessair) seems unrelated to the first invader of Ireland in Lebor Gabála [Book of Invasions]. Úgaine divided Ireland equally among his twenty-five children, but only two of them, Cobthach and Lóegaire Lorc, father of Labraid Loingsech, had any children themselves.