Maurice FitzGerald was the half-brother of Robert FitzStephen, and took part in the initial Anglo-Norman invasion of Ireland in 1169. He was subsequently granted lands at Naas in North Leinster (modern-day County Kildare) and was the progenitor of the twin FitzGerald dynasties of Kildare and Desmond.
Reference: National Library of Ireland Expugnatio Hibernica by Gerald of Wales (date: completed 1189) By permission of the Council of Trustees of the National Library of Ireland.
