Eugein II may have been ruler of Alt Clut, the Brittonic kingdom later known as Strathclyde, for some time in the late-8th century.^[1] He is known only from the Harleian genealogies (British Library, Harley MS 3859), which indicate that he was the son of King Dumnagual III of Alt Clut;^[2] there is no direct evidence that he ruled as king himself. Dumnagual is presumed to be the monarch who submitted to the joint army of Kings Óengus I of the Picts and Eadberht of Northumbria in 756; after this event, Alt Clut seems to have remained under foreign power and the royal line is known exclusively through the Harleian genealogies for more than a century.^[3] If Eugein was king, he may have been in power during the "burning of Ail Cluaithe" recorded in the Annals of Ulster as having occurred in 780.^[4] According to Harleian, he was the father of Riderch II.^[2]