Facts and Events
Donnell was a son of King Tairrdelbach Ua Conchobair of Connacht (1088-1156 and Derbforgaill Ni Lochlainn (died 1151. Derbforgaill was the daughter of King Domnall Mac Lochlainn of Ailech, and one of Tairrdelbach's six wives.
Domnall's full siblings were Aed Dall Ua Conchobair (blinded 1136) and Cathal Migaran (died 1152. He was nicknamed Mideach because he was fostered in Mide, possibly by King Murchad Ua Mael Sechlainn (died 1153.
He succeeded his brother, Conchobar Ua Conchobair, as tainiste of Connacht upon the latter's assassination in 1144 but was opposed by another brother, Ruaidhri Ua Conchobair. Domnall led military campaigns on behalf of his father between 1145 and 1148, but in 1152 was imprisoned by his full-brother, Cathal Migaran. He seems to have subsequently fallen from favor with his father, who replaced him as tainiste with Ruaidhri, who would become king in 1156.
Clann Bhriain an Bhuid in An Corran was from Domnall Mor of An Cheis s.[son] of Tiordhealbach Mor.