Cosimo de'Medici (1642-1723), Grand-Duke of Tuscany as Cosimo III, visited England in 1669. Among those who came to pay their respects to him in London was Samuel Cooper. Cosimo had heard of Cooper's ability and had been told that 'no person of quality visits that city without endeavouring to obtain some of his performances to take out of the Kingdom' (D. Foskett, Collecting Miniatures, Woodbridge, 1979, p. 95). He sat for Cooper on 1 June 1669 and this was to be the first of several sittings but the portrait was not finished until he left England at the end of the following year. Cosimo had by then succeeded his father as Grand-Duke of Tuscany and Lord Philip Howard paid Cooper £50 for the miniature on the Grand-Duke's behalf. Cooper probably made several sketches during these sessions which would account for the difference between the version in the Uffizi (exhibition catalogue Samuel Cooper and his Contemporaries, London, National Portrait Gallery, 1974, no. 128) and the present miniature. The present portrait is close to the style of Cooper and appears to be a copy of his work by Susan Penelope Rosse. She, according to Vertue, 'being inamour'd with Coopers limnings she studied and coppy'd them to perfection.' How closely she copied Cooper's work is shown in the sketch book of which the contents were attributed to her but have lately been revealed to be partly her work and partly that of Samuel Cooper (see G. Reynolds, Samuel Cooper's Pocket-Book, London, 1975).
For an account on Susan Penelope Rosse, see J. Murdoch, Seventeenth-century English Miniatures, London, 1997, pp. 235-236.