Marquess of Rockingham
On 22 June 1744 at St George's, Hanover Square, Lord Fitzwilliam was married to Lady Anne Watson-Wentworth, daughter of the Earl of Malton. Lord Malton was later created Marquess of Rockingham; Lady Anne's brother was the future Prime Minister Charles Watson-Wentworth. Lord and Lady Fitzwilliam had two sons and six daughters: