 Lacking sources, it cannot be demonstrated that the Cotters of Cork or Mac Ottir of Dublin descend from this Jarl Ottar, but he did live in the right period for his name to be adopted as a surname.For example, the famous O'Neill dynasty take their name from his contemporary Niall Glúndub, who also died in battle.In 1014 a Norse-Gael leader called Ottir Dub (Óttar the Black), a possible descendant of Ottir Iarla, is recorded as fighting on the side of Sigtrygg Silkbeard the King of Dublin against Brian Boru, High King of Ireland, at the Battle of Clontarf.