This portrait was painted when the sitter was three years and six months old, according to a mezzotint of the painting by William Faithorne, c.1695, which confirms the identity of the sitter and artist. A copy of this mezzotint is is held by the National Portrait Gallery, London and the Royal Collection. The canvas is framed in the same magnificent original 'Longleat' frame, seen on many other portraits which remain at Longleat House, Wiltshire, the family seat of the 7th Marquess of Bath.

 James Thynne was the youngest son of Thomas Thynne, 1st Viscount Weymouth and Frances Finch of Longleat House, Wiltshire. He died in his youth and his Aunt, Anne Kingsmill Finch, Countess of Winchilsea (1661-1720), wrote a moving poem on his death. He was buried in the family vault at Longbridge Deverill, Wiltshire.  

Johann Kerseboom (d.1708) was the nephew of Frederick Kerseboom and first worked in Germany before coming to England in the 1680's where his sitters included the 'Electress Sophia Dorothea' (known from a mezzotint by William Faithorne). His early works were influenced by William Wissing through his early collaboration with him but he developed his own style, demonstrated in his portrait of 'Robert Boyle', of which several versions are found in the Royal Collection and the National Portrait Gallery.  He collaborated with his close friend Jan Van der Vaart on works such as the portrait of 'Thomas Osborne, First Duke of Leeds' (1704, London NPG) and the portrait of 'Gilbert, Fourth Earl of Coventry' ( dated 1704, Antony House, Cornwall) which is signed by both artists.

He died in London in 1708, leaving his estate to Van der Vaart. In his words 'I stand indebted and doe owe unto my very loveing Friend John Vander Vaart of the parish of St Paul Covent Garden in the county of Middlesex a considerable sume of money which I am not at present able to pay....Therefore in Satisfaction I give and bequeath unto the said John Vander Vaart All my Estate'.