This Aibhne O'Cathain, son of Cooey,and grandson of Rory of the Route took over the chieftaincy of the O'Cathain Sept from his father. Aibhne O'Cathain was chief during the great days of Shane "the Proud" chief of the O'Neills, and master of all Ulster. O'Neills rebellion against the English resulted in 1567 the statute attainting O'Neill attainted to O'Cathain also, and all O'Cathain lands were declared to be forfeited to the Crown of England. Aibhne O'Cathain managed to remain on good terms with the English and no attempt was made to seize O'Cathain lands.
He was drown in the Bann river. He was succeeded by Rory O'Cathain, son of Manus.