Norman invasion of Ireland: English and Irish forces conquered Dublin, forcing Ascall mac Ragnaill, the last Norse–Gaelic king of Dublin, into exile. Anglo-Norman invasion of Ireland: The Anglo-Norman invasion of Ireland took place during the late 12th century, when Anglo-Normans gradually conquered and acquired large swathes of land in Ireland over which the kings of England then claimed sovereignty. The Anglo-Normans claimed the invasion was sanctioned by the papal bull Laudabiliter. At the time of the invasion, Gaelic Ireland consisted of several kingdoms, with a High King claiming lordship over most of the other kings. The Anglo-Norman invasion was a watershed in Ireland's history, marking the beginning of over 800 years of British presence in Ireland. September 21, 1170. Wiki link