This is a list of Irish monarchs since the country's unification in 1228. Until that point, the island was divided in various petty kingdoms (Ulidia, Oriel, Breifne, Aleich, Connacht, Meath, Leinster and Munster). following the Norman invasion of Ireland, Ulidia, Oriel, Aleich and Breifne were annexed by the Normans. Meanwhile, Connacht, Meath and Leinster merged (Munster was annexed by Leinster in 1138.), and under the lead of Domnhall mac Murchada, King of Leinster, the Normans were expelled from Ireland, and the Norman conquered territory was integrated into Ireland.