William Croone (1633–1684) was born in London and educated at Cambridge University. He was made Professor of Rhetoric at Gresham College in 1659 and shortly after this was appointed secretary to the Royal Society, of which he was one of the original fellows.

Croone became fellow of the Royal College of Physicians in 1675, and when he died he left instructions for an annual lecture to be given at the College, and at the Royal Society, on the subject of the nature and laws of muscular motion. His will did not include funds for these lectures, but fortunately his widow remarried to a wealthy man and was able to fund the lectureships on Croone’s behalf.

The portrait is by the English portrait painter Mary Beale. She became one of the most important portrait painters of seventeenth-century England, and has been described as the first professional female English painter.