Portrait of Sir William Monson, 4th Bt. (c. 1653-1727), three-quarter-length, before a column, a landscape beyond

Celebrated in his day, John Riley was described by the aesthete Horace Walpole (1717-1797) as "one of the best native painters that has flourished in England."

The sitter was the second son of Sir John Monson of Burton, Lincolnshire (1628-1674). On 18 July 1688, he married Laetitia, daughter of John Poulett, 3rd Baron Poulett (c. 1641-1679) and succeeded his brother as 4th Bt. on 6 April 1718. In the early 1690s he was involved in lead mining enterprises in North Wales and a scheme to establish a company of London glassmakers. A convinced Whig, he represented Lincoln (1695-98), Heytesbury (1702-08), Hertford (1708-10), and Aldborough (1715-21) in the House of Commons.