 The MacDonnells already possessed Dunnyvaig Castle on the Isle of Islay and lands in Kintyre, Scotland.The MacDonnells of Antrim did not become a separate branch of Clan Donald until 1558, when they were part of Clan MacDonald of Dunnyveg, when Somhairle Buidhe MacDonnell obtained the lordship of the territory in Ireland from James MacDonald, 6th of Dunnyveg.John Mor was assassinated by James Campbell in 1427.