Portrait of a gentleman, traditionally identified as John Locke, three-quarter-length, in a russet gown, pointing at an oval portrait of a gentleman, thought to be John Milton

The sitter in this portrait bears some resemblance to the philosopher, John Locke (1632-1704), although his nose appears more pronounced in this image than in other identifiable portraits for example John Greenhill's portrait (circa 1672-1676; National Portrait Gallery). The figure to whom the sitter is gesturing may represent an idealised, posthumous image of the young John Milton (1608-1674), and is close to engravings of him by William Fairthorne and Jonathan Richardson, although in these Milton is shown with a central parting.

John Locke, the elder son of John Locke (1606-1661), attorney, and his wife, Agnes (1597-–1654), daughter of Edmund Keneo, was born on 29 August 1632, at Wrington, Somerset. A friend and supporter of Lord Shaftesbury, Locke was associated with the opposition to both King Charles II and King James II, and was forced to flee to Holland in 1684. He returned to England on the accession to the throne of William and Mary and was made Commissioner of Appeals. A champion of empirical thought, Locke was celebrated for his essays on religion, education and politics, and his best known work was An Essay concerning humane understanding and treatises on Government (1680). He was also an active member of the Royal Society, which broadly promoted scientific exploration.