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
History of Northamptonshire of mention. Only a large mound and visible earthworks remain of the castle at Fotheringhay, famous as the scene of the imprisonment, trial and execution of Mary, Queen of Scots. Part of the house which was the birthplace of Richard III still stands and is now a private dwelling. Barnwell Castle, founded by William the Conqueror, an interesting example of the defensive construction of the period, is still a fine ruin, which includes four of the round towers and an imposing gateway. Holdenby Manor House, where Sir Christopher Hatton (1540–1591) was born, and where Charles I was staying when he