Andrew Benjamin Lens was the son of Bernard Lens, the first artist in England to work in watercolour on ivory rather than vellum. Working on ivory was the invention of the Venetian artist Rosalba Carriera (1675-1757). Lens’s earliest known work on ivory dates from 1707. He also worked on vellum, catering for the consciously old-fashioned taste of some collectors. This miniature is one of a series by father and son of portraits of English kings, queens and, in this case, Oliver Cromwell, who represents the Commonwealth period between the execution of King Charles I in 1649 and the restoration of the monarchy in 1660.

This miniature is on vellum and has the solid blue background typical of Tudor and early Stuart miniatures, and so appears to be a ‘traditional’ miniature of an historical character. Early 18th-century antiquarians had a passion for collecting so-called ‘heads’ - portraits of famous people. Horace Walpole, an amateur pupil of Bernard Lens, typified this mania, with a collection of thousands of prints and paintings of famous people.