James Fitzwilliam

James Fitzwilliam (died 1420) was an Irish landowner and judge who held the office of Chief Baron of the Irish Exchequer. He was the ancestor of the prominent Dublin landowning family which acquired the titles Viscount FitzWilliam and Earl of Tyrconnell.

He was the son of Hugh Fitzwilliam. The Fitzwilliam family are recorded in Dublin from about 1210. By the time of James' birth they were already considerable landowners in Dublin, centred on Dundrum and Swords.

Few details of his legal career survive, but it is known that he was Chief Baron by 1413 and was superseded in 1417.

He married, after 1390, a daughter of Sir John Cruise, one of several marriages between the two families. Cruise was a distinguished diplomat and soldier and a major landowner in Dublin, who held the manors of Mount Merrion, Stillorgan and Thorncastle, which comprises roughly modern Booterstown. Merrion Castle, Sir John's principal dwelling, subsequently became the main Fitzwilliam residence.

James died in 1420, and his lands passed to his son, Phillip, who was still a minor; the family estates are said to have suffered serious depredation during his minority He was a ward of his father's successor as Chief Baron, James Cornwalsh; ironically Cornwalsh was murdered 20 years later in a private war with the Fitzwilliams, although Philip himself was not, as far as is known, personally involved in the feud.