Cormac mac Art Ó Melaghlain, was King of Mide from around 1209/10 to 1239. He managed to win several notable victories over the Anglo-Normans and as a result was one of the more prominent and successful later Kings of Mide. 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.