From his base west of the river Shannon, he was forced to deal with the Norman invaders and was a competent leader despite his problems, avoiding major conflicts and winning minor skirmishes.

He is the subject, as Cáhal Mór of the Wine Red Hand, of the poem A Vision of Connaught in the Thirteenth Century by the 19th-century Irish nationalist James Clarence Mangan.

[4] Crobhdearg had wanted to engage William de Burgh and Carragh but his allies refused and turned back north only to be caught up with and defeated by the very army they had sought to avoid.

[4] Soon after he gained the aid of John de Courcy who marched against Carragh on his behalf only to be defeated as well, with Crobhdearg taken prisoner by the Normans of Meath as he could no longer pay their promised wages, but released the same year and re-inaugurated on the stone at Clonalis.

[4] In 1224 Cathal wrote to Henry III as Lord of Ireland, again asking that his son and heir Od (Aedh) be granted all of Connacht, in particular those parts, Breifne, owned by William Gorm de Lacy.

[7] He died in the same year and was succeeded by his son, Aedh mac Cathal Crobdearg Ua Conchobair ''for he had been king by the side of his father (rí ri láim a athar) and already held all the hostages of Connacht.

And God granted him this kingdom, for no crime was committed in Connacht at the moment of his accession save one robbery on the road to Cruach, and the hands and feet of the robber were cut off, and the violation of one woman by O Mannachan's son, who was blinded forthwith for the offence.