Sir John de Courcy (1150–1219) was an Anglo-Norman knight who arrived in Ireland in 1176. From then until his expulsion in 1204, he conquered a considerable territory, endowed religious establishments, built abbeys for both the Benedictines and the Cistercians and built strongholds at Dundrum Castle in County Down and Carrickfergus Castle in County Antrim. Early career in Ireland Belonging to a family which took its name from Courcy, Calvados, John de Courcy came to Ireland around the year 1171 as part of the Norman invading forces, brought in as mercenaries working for Diarmaid Mac Murchadha, the ousted King of Leinster, to help him regain his position as king. De Courcy's exact parentage is unknown. The man thought to be his great-grandfather, Richard de Courcy is named in the Domesday Book. De Courcy's grandfather, William de Courcy I, married Emma de Falaise. His father, William de Courcy II, married Avice de Rumilly and died before 1130, leaving the family estates in Somerset and elsewhere in England to his son, William de Courcy III, John’s possible brother. John was very ambitious and wanted lands for himself. He decided to invade the north of Ireland which was controlled by Irish dynasties. In early January 1177, he assembled a small army of 22 knights and 300 foot-soldiers and marched north, at the rate of thirty miles a day. They skirted the back of the Mourne Mountains and took the town of Dún Dá Leathghlas (now Downpatrick) by surprise. After two fierce battles, in February and June 1177, de Courcy defeated the last King of Ulaid, Ruaidhrí Mac Duinnshléibhe. He did all this without King Henry II's permission. After conquering eastern Ulster, he established his seat at Carrickfergus, where he built an impressive stone castle. Other monasteries and castles that he built are Inch Abbey and Dundrum. He married Affrica, daughter of Godred II Olafsson, King of Mann. It is likely that the marriage, as in the case of many kings and those aspiring to be kings in those days, was political, to seal an alliance with her father who paid homage to the King of Norway. John and Affreca are not recorded to have had any children. Affreca built a monastery at Greyabbey dedicated to Saint Mary of The Yoke of God. She is buried there and her effigy, in stone, can still be seen. In 1183, de Courcy provided for the establishment of