The Irish Family [ of Eustace] came from Normandy at the time of the Conquest. Around 1100, Eustace FitzJohn inherited the castles of Bamburgh and Knaresborough from his uncle Serlo de Burgh to which Alnwick castle was added on his marriage to Beatrice de Vesci. His second marriage, to Agnes of Halton, brought him the castle at Halton and hereditary constableship of Chester. He was among the most powerful men in the north. His sons of the first marriage took their mother's family name of de Vesci. The son of the second marriage, Robert, married Aubrey de Lisours who was a daughter of the de Lacy family and brought him lordship of Pontefract. Their eldest grandson took the name de Lacy in order to inherit from his great-uncle. His brother, John FitzEustace went with Hugh de Lacy in Strongbow's expedition to Ireland and founded the family in Dublin and County Kildare around 1180. The prefix Fitz' was dropped about 1300.