The man stands before a formal garden at the right and rests his arm on a pedestal decorated with a relief of a cupid overcoming Pan. The sitter was formerly identified as 'Admiral Lord Berkeley' but none of the admirals who were members of the Berkeley family was of the age of this sitter in 1679, the date inscribed on the portrait. If he is one of the earls of Berkeley the only reasonable candidate is Charles, the 2nd Earl (1649 - 1671), who was envoy to the States of Holland (1689-94). However, the only portrait which claims to represent Charles shows a different man.
In the past this painting has been attributed to Caspar Netscher, while he was a student of Gerard ter Borch, but it is now considered to be a studio replica of a painting (Amsterdam, Rijksmuseum) dated 1678.
The signature and date are not in Netscher's hand and were presumably added later.
