The MacArthurs are Celts. A tribe of this clan were hereditary pipers to the MacDonalds of the Isles. MacArtair aided Robert the Bruce, from whom he received the forfeited estates of MacDougall. John MacArtair held princely state; but this ended when a later MacArtair was beheaded by James I, and his lands were forfeited.
In later days the MacArthurs gained part of Strachur, in Cowal, Argyllshire, and also owned a portion of Glenfalloch and Glendochart. The family seat of the MacArthurs of Tir-a-cladich was on Loch Awe side. The title Mac-ic Artair suggests that Tir-acladich was a cadet of the main MacArtair line.

Chief: MacArthur of Tirracladdich.
Patronymic: Mac-ic-Artair.
Clan Seat: Tirracladdich on Loch Awe, Argyll.
Slogan: Eisd! 0 Eisd
Plant: Wild Thyme.