Brian's first wife was Mór, daughter of the king of Uí Fiachrach Aidne of Connacht. She is said to have been the mother of his sons Murchad, Conchobar and Flann. Later genealogies claimed that these sons left no descendants, although in fact Murchad's son Tadc is recorded as being killed at Clontarf along with his father and grandfather.[10] Echrad daughter of the king of Uí Áeda Odba, an obscure branch of the southern Uí Néill, was the mother of Tadc, whose son Toirdelbach and grandson Muirchertach rivalled Brian in power and fame.[11] Brian's most famous marriage was with Gormflaith, sister of Máel Mórda of Leinster. Donnchad, who had his half-brother Tadc killed in 1023 and ruled Munster for forty years thereafter, was the result of this union.[12] Brian had a sixth son, Domnall. Although he predeceased his father, Domnall apparently had at least one surviving child, a son whose name is not recorded. Domnall may perhaps have been the son of Brian's fourth known wife, Dub Choblaig, who died in 1009. She was a daughter of King Cathal mac Conchobar mac Taidg of Connacht.[13] Brian had at least three daughters but their mothers are not recorded. Sadb, whose death in 1048 is recorded by the Annals of Innisfallen, was married to Cian, son of Máel Muad mac Brian. Bé Binn was married to the northern Uí Néill king Flaithbertach Ua Néill. A third daughter, Sláni, was married to Brian's stepson Sitric of Dublin.[14] According to Njal's Saga, he had a foster-son named Kerthialfad.[15]

http://en.wikipedia.org/wiki/Brian_Boru