William FitzWilliam (Lord Deputy) William FitzWilliam (Lord Deputy) Sir William FitzWilliam (1526–1599) was an English Lord Justice of Ireland and afterwards Lord Deputy of Ireland. In 1587, as Governor of Fotheringhay Castle, he supervised the execution of the death sentence on Mary, Queen of Scots. He was the Member of Parliament for Peterborough and represented County Carlow in the Irish House of Commons. He lived at Gainspark, Essex, and Milton Hall. FitzWilliam was born at Milton Hall, Northamptonshire, the eldest son of Sir William (d. 1576) and grandson of William Fitzwilliam, Sheriff of London, who had been treasurer and chamberlain to Cardinal Wolsey and
Fotheringhay Castle confiscate many baronial castles; this proved unpopular with the barons and, to appease them, John began reversing his actions in 1215. Fotheringhay was amongst the castles he returned to their previous owners that year. David, Earl of Huntingdon, rebelled against the king, and his property was granted to William Marshal, 2nd Earl of Pembroke. In 1218, Marshal had been ordered to return the earl's estates, but had retained possession of at least Fotheringhay Castle. When David died in June 1219, the Earl of Pembroke still held Fotheringhay despite King Henry III of England. Alexander II, King of Scotland, had a