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
William FitzWilliam (Lord Deputy) allowed to resign his office. After his return to England in 1575 FitzWilliam was appointed governor of Fotheringhay Castle, where he supervised the execution of the death sentence on Mary, Queen of Scots. In 1588 FitzWilliam was again in Ireland as Lord Deputy, and although old and ill he displayed great activity in leading expeditions, and found time to quarrel with Sir Richard Bingham (1528–1599), the new President of Connaught. He relied heavily on the Lord Chief Justice of Ireland, Sir Robert Gardiner, and refused his pleas to be allowed to retire on health grounds, saying that Gardiner was so