Cathal (d. 925), son of Conchobar and king of Connacht, belonged to the Síl Muiredaig lineage of Uí Briúin Aí, which had virtually monopolised the provincial kingship of Connacht since the second half of the eighth century. His immediate predecessors in the kingship were his father Conchobar (d. 882) and his brothers Áed (d. 888) and Tadc (d. 900). Another brother, Máel-cluiche, died in 913. After his accession as king of Connacht (900), Cathal took part in a rígdál (royal meeting) with the Uí Néill high-king Flann Sinna (qv) at the ecclesiastical settlement of Clonmacnoise. The choice of venue alone, given the widely recognised Uí Néill patronage of Clonmacnoise at this time, would suggest that Flann Sinna and not Cathal was setting the agenda. Indeed, Cathal's subordinate position would seem to be emphasised by the fact that in 908 he, along with Cerball (qv) son of Muirecán, king of Leinster, rallied to support the high-king against the ambitious Munster ruler Cormac (qv) son of Cuilennán at the battle of Belach Mugna (barony of Idrone, Co. Carlow). The extent to which Cathal and the Uí Briúin Aí cooperated with Uí Néill in accepting prescribed spheres of influence was offset, however, in the course of the tenth century by the expansion of the rival Connacht dynasty of Uí Briúin Bréifne into the midlands. Dying in penitence in 925, Cathal was succeeded by his son Tadc (d. 956), from whom most of the later kings of Connacht descended (Rawl. B. 502, 145e 29; LL, 338 f. 7).
AU; AFM; Bk Leinster, vi, 1489; O'Brien, Corpus geneal. Hib., 172; Byrne, Ir. kings, 266, 300–301