Whatever gains Cormac made were not to prove long lasting however, even in his own reign, and the successor lords of Clann Cholmain were largely insignificant to the politics of later medieval Ireland.
Despite, or perhaps because of, its situation in central Ireland, Mide found itself being used as a pawn in the power-struggles of the newly-dominant kingdoms, as real power on the island shifted to the previously marginalized dynasties of Leinster, Munster and Connacht as well as their northern Uí Néill kinsmen.
Its past sponsorship of large numbers of monasteries ate into the kingdoms resources and its failure to secure over-lordship of Dublin, the islands economic capital, meant they would never again produce a High King of Ireland.
[12][13] He also plundered the English castle of Kilclare for horses and other loot prompting an expedition against him where he was defeated at the battle of Tine Bridge in 1213 and forced to relinquish his newly acquired land.
Art would go on to have a relatively successful reign for a later King of Mide also, defeating the English of Meath in 1264 reasserting control over lands his father had lost after the battle of Tine Bridge and gaining the submission of many local chieftains.