Dated to circa 1769, this monumental canvas is the artist’s grandest statement on the theme of Mares and Foals, the series of paintings executed in the 1760s which arguably stand as Stubbs’ crowning achievement. The picture is believed to have been painted for the Prime Minister of Britain from 1768-1770, Augustus Fitzroy, 3rd Duke of Grafton (1735-1811), who was part of the closely-connected nexus of ‘Whig’ statesmen that provided Stubbs with his most important patronage during this career-defining period. Having only appeared at auction once before, almost 50 years ago, it will be on public view in New York from 18 to 22 May, and in the pre-sale London exhibition which runs from 28 June to the morning of 2 July.