In 1071 , the year before his grandfather 's death , Domnall and an Uí Chennselaig kinsman , Donnchad mac Domnaill Remair , battled for control of Leinster . Although Domnall is accorded the title King of Leinster in one mediaeval king @-@ list , Donnchad was evidently a more powerful claimant , and Domnall appear to have held the Leinster kingship in name only .