Marquess of Rockingham
William Wentworth-Fitzwilliam, 4th Earl Fitzwilliam, PC (30 May 1748 – 8 February 1833), styled Viscount Milton until 1756, was a British Whig statesman of the late 18th and early 19th centuries. In 1782 he inherited the estates of his uncle Charles Watson-Wentworth, 2nd Marquess of Rockingham, making him one of the richest people in Britain. He played a leading part in Whig politics until the 1820s.