Alisdair Mór, son of Donald of Islay and great-grandson of Somerled, was a 13th-century Gaelic noble whose life is known only through scattered historical records. Records describe Alisdair Mór as "of Antrim" - along the coast of Northeast Ireland, later a Donald stronghold. He was the ancestor of Clan Alasdair (MacAlister) and historical sources note that he was praised in the Irish Annals as "the most distinguished of his name" for his hospitality and military skill.  Alisdair Mór and many of his followers were killed in 1299 by Alisdair MacDugall.  His descendants were identified by his name and not simply as members of the great Clan Donald. This carried enough weight to eventually form a distinct clan.