Kingdom of Desmond
MacLochlainn's plans to restore the High Kingship to the north was thwarted by his ally Tairrdelbach Ua Conchobair of Connacht who formed an alliance with the O'Brien's. In 1118 Conchobair partitioned Munster between the sons of Diarmait and Tagh Mac Carthaig. The northern section of the province became the O'Brien Kingdom of Thomond ("Tuadh Mhumhain" "North Munster") and the southern became the Mac Carthaigh Kingdom of Desmond ("Deas Mhumhain" "South Munster").