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
English invasion of Scotland (1482) James Douglas. Edward IV seized this new opportunity to invade Scotland, hired Master Douglas and his ship on 9 May, and summoned fighting-men for the cause of the "king of Scotland" on 10 May. Edward IV, Albany and Richard, Duke of Gloucester made a formal treaty at Fotheringhay Castle near Peterborough, where Mary, Queen of Scots was imprisoned and executed a century later. According to the Fotheringhay treaty, Alexander, if he became King of Scotland, would reserve to Edward IV the town of Berwick upon Tweed, Lochmaben Castle with land in southern Scotland in Annandale, Liddesdale, Eskdale and Ewesdale. He