1171 in Ireland

Events

• May – following the death of Diarmait Mac Murchada, King of Leinster, the lordship of Leinster is disputed between his son, Domhnall Caomhánach, and the Cambro-Norman Richard de Clare.
• Henry II of England arrives in Ireland; Irish bishops and most Irish kings submit to his rule.
• Ascall mac Ragnaill, last Norse–Gaelic King of Dublin, is captured while trying to retake Dublin from de Clare, perhaps in company with Sweyn Asleifsson, and beheaded; before the end of the year, de Clare relinquishes possession of the city to his own liege lord, Henry.

  Deaths

• 1 May – Diarmait Mac Murchada, King of Leinster.
• Ascall mac Ragnaill, King of Dublin.