Kingdom of Desmond
MacLochlainn's plans to restore the High Kingship to the north was thwarted by his ally Tairrdelbach Ua Conchobair of Connaght 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 and the southern became the Mac Cathaig Kingdom of Desmond.