O'Flaherty (Middle Irish: Ó Flaithbertaigh; Modern Irish: Ó Flaithearta), is an Irish Gaelic clan based most prominently in what is today County Galway. The clan name originated in the 10th century as a derivative of its founder Flaithbheartach mac Eimhin. They descend in the paternal line from the Connachta's Uí Briúin Seóla. They were originally kings of Maigh Seóla and Muintir Murchada and as members of the Uí Briúin were kinsmen of the Ó Conchubhair and Mac Diarmata amongst others. After their king Cathal mac Tigernán lost out to Áed in Gai Bernaig in the 11th century, the family were pushed further West to Iar Connacht, a territory associated with Connemara today. They continued to rule this land until the 16th century.