Cailean was the son of Gilleasbaig, a knight and lord of the estates of Menstrie and Sauchie in Clackmannanshire.
[3] This means that Cailean himself was the cousin of the future king, Robert I of Scotland, which explains why the Campbells were so attached to the Bruce cause during the Wars of Scottish Independence.
[4] Cailean himself took part in the Great Cause, and was one of the Bruce representative advocates to King Edward I of England in 1291.
He appears in the Newbattle Registrum of around 1293, where he is called the son of "Gylascop Kambel" ("Gilleasbaig Caimbeul"), obtaining from Sir Robert Lindsay the estate of Symington; the document, which has James Stewart, 5th High Steward of Scotland, Lord of Kyle, as one of Cailean's pledgers, guarantees continued payment of rent to Newbattle Abbey.
[6] A cairn called Carn Chailein, located within 2 km of Kilbeg on Loch Avich, is traditionally said to mark the place where Cailean was killed.