Contested Kingdoms
Muirchertach Ua Briain entered the year as king of Munster, but his position had not been secured peacefully. On Tairdelbach’s death, Munster had initially been divided among his sons Tadc, Muirchertach and Diarmait. Tadc died within a month, while Diarmait was expelled and Muirchertach claimed the kingship. This recent family rupture shaped the conflict of 1087. Muirchertach inherited considerable resources, links with the Hiberno-Norse towns and the prestige of the Dál Cais, yet his father’s authority over other provinces could not simply be inherited. Irish overkingship depended upon personal military success, negotiated submission and the continued cooperation of lesser kings.