 Domnall was a son of Murchad mac Diarmata , King of Dublin and the Isles ( died 1070 ) , who was himself a son of Diarmait mac <unk> na mBó , King of Leinster ( died 1072 ) . Domnall was , therefore , a member of the Uí Chennselaig ; as well as the first of the <unk> Murchada , a branch of the Uí Chennselaig named after his father . Domnall had two brothers : Donnchad ( died 1115 ) , a later King of Leinster , and <unk> . 
