 Donnchadh (Donogh) mac Conchobhair Ó Briain, was the eldest son of Conor O'Brien, 3rd Earl of Thomond, and his second wife, Una, daughter of Turlough Mac-i-Brien-Ara.Donogh was brought up at Elizabeth's court.There he was residing in 1577, when he was mentioned as Baron of Ibrickan in the new patent granted on 7 October to his father.