Robert Smythson, architect and mason, was 79 at the time of his death. However, there is no evidence that indicates the exact date or year of his birth.
There is evidence to suggest, however, that Smythson was working at Longleat House, Wiltshire, England by 1568 where he was employed as master mason by Sir John Thynne. Within 10 years Smythson is known to have been working on alterations at Wardour Castle, Wiltshire for the Arundell family. The castle later became a picturesque feature within the 18th-century landscape developed by a later generation of the family.
It has been suggested that Robert Smythson's connection with Wardour provided him with his commission at Wollaton Hall in Nottinghamshire. There he was Surveyor of the Works between 1530 and 1588. Other notable works or commissions in England included Hardwick Hall, Derbyshire (1590-1); Burton Agnes, Yorkshire (1601-10); and Welbeck Abbey, Nottinghamshire, all of which reveal Smythson's firm understanding of classical architecture.
His son, Sir John Smythson also worked at Wollaton, in the service of the Cavendish rather than the Willoughby family. Robert died at Wollaton on 15 October 1614.