 Many of the present day McDonnells have a common descent from Sorley Boy MacDonnell.The MacDonnells of Antrim are descended from John Mor MacDonald, chief of the Clan MacDonald of Dunnyveg.John Mor MacDonald was the second son of "Good" John of Islay, Lord of the Isles, 6th chief of Clan Donald, through John of Islays second marriage to Princess Margaret Stewart, daughter of King Robert II of Scotland.