The portrait of Major Robert Thompson (1622-95) (above) is priced in the region of £40,000.
Harrison bought the unattributed portrait painted c.1655 at an auction in Italy in 2020 and began research based on a label for the early 20th century Paris dealership Galerie Sedelmeyer.
A Sedelmeyer catalogue c.1907 described the sitter as Thompson, a naval commissioner whose family counted Oliver Cromwell as a friend. Thompson was considered a potential husband for one of Cromwell’s daughters at some point and this portrait was painted in the mid-1650s when Thompson was out to impress.
Harrison said: “By being painted in gilt armour, which would have cost huge sums of money despite being out of fashion at the time, Thompson wanted to show off to Cromwell. Shortly before painting Robert’s portrait, Lely had depicted Cromwell himself [a pictured owned by Birmingham Museums], bolstering his place as the greatest artist active in England.”
Art historians Catharine MacLeod and Diana Dethloff, who are working on a catalogue raisonné of Lely’s paintings and drawings, agreed it is by Lely.