Colla Da Crioch was one of three brothers of royal lineage who lived in the Fourth Century A.D. At the beginning of the Fourth Century Fiacha was High King and his son, Muiredach was appointed King of Connaught. To be appointed as King of Connaught was usually perceived as a stepping stone to the High Throne at Tara. Colla Da Crioch’s two other brothers were named Colla Uais and Colla Maen. Colla Uais attempted to succeed Fiacha as High King instead of Fiacha’s son Muiredach. While Muiredach was in Munster fighting a battle Colla Uais with his two brothers attempted to seize the throne at Tara and gave battle to the High King Fiacha at Taillten in Meath where Fiacha was killed. Colla Uais managed to seize the throne at Tara and he reigned for four years. At the end of that period he was overthrown by Muiredach, the son of the slain King Fiacha. Colla Uais and his two brothers fled to Scotland and found refuge with the King of the Picts. Muiredach became High King of Ireland and reigned for 27 years.


In the third year of his reign the three Collas returned and made another attempt to seize the throne. Muiredach was aware of this and persuaded them to use their talents in subduing the Kingdom of Ulster. The three brothers raised an army and attacked Ulster. The reason given was that some generations before the Ulster King Tiorbraide had slain the High King Conn of the Hundred Battles. The two armies met on the plains of Farney in modern day Monaghan and the Ulster men led by King Fergus were defeated. Fergus was slain and the Ulster men confined to territory east of the river Bann. Out of the ruins of the Kingdom of Ulster grew the new Kingdom of Oriel. The Carroll of Oriel family trace their descent to Colla Da Crioch.