 The founder of Clan Donald of Dunnyveg and the Glens was Eòin Mòr Tànaiste Mac Dhòmhnaill who was the second son of John MacDonald also known as "Good" John of Islay, Lord of the Isles, 6th chief of Clan Donald and 1st Lord of the Isles through his marriage to Margaret Stewart.Eòin Mòr Tànaiste Mac Dhòmhnaill married Margaret Bissett of the Glens of Antrim.From his marriage he claimed, but did not possess, this territory in Ireland, along with those he already possessed in Islay and Kintyre in Scotland.