Clan Ewen of Otter claimed descent from Donnsleibhe,[1] who was said to be a descendant of an Irish prince of the O'Neill dynasty named Ánrothán Ua Néill, who left Ireland for Kintyre in the 11th century.
[2] The only genealogy to survive regarding Clan Ewen of Otter, is the so-called MS 1467, now held in the National Library of Scotland.
[1] Another origin suggested by earlier writers posited descent from the 13th-century Ewen Mac Dunslebhe, whose brother Fearchar is the ancestor of Clan Lamont.
In March 1432, Swene MacEwen resigned his title to the Barony of Otter to his feudal lord, King James.
[2] Since the death of Swene the line of chiefs of the MacEwens of Otter has been untraced,[2] however according to tradition, a MacEwen clan arrived in the earldom of Lennox "under a chieftain of their own" during the fifteenth century; the same tradition, which refers to a new banner, suggests that the clan chief was granted arms by Mary Queen of Scots at some time before her defeat at The Battle of Langside in 1568.