One of the National Gallery's most popular paintings has become the centrepiece for its newest exhibition. The stark, iconic image of the horse Whistlejacket greets visitors to Stubbs and the Horse, the first British exhibition to be devoted to the paintings of George Stubbs.

Commissioned in about 1762 by the Marquess of Rockingham,Whistlejacket confirmed Stubbs's reputation as the greatest painter of horses in the history of art.

He became the most successful British equine painter after undertaking 18 months' intensive investigations into horse anatomy. He hid himself away at a farmhouse in Horkstow, Lincolnshire, in the late 1750s to dissect horses at a time when not even the human form was fully understood.

His studies paid off when he began producing his heroic studies of horses just as British racing was entering a golden age. New thoroughbreds, nearly all descended from just three Arab stallions, were racing faster and raising stakes for owners and gamblers alike.

The exhibition - which opens today - includes works lent by the Queen, the Royal Academy and the Yale Centre for British Art. The subjects include some of the most famous names in racing folklore, and the aristocrats who bred them. Gimcrack, one of the most popular and admired 18th-century horses, won 28 out of his 36 races despite being unusually small. Gimcrack on Newmarket Heath, with a Trainer, a Stable-Lad, and a Jockey (1765) commemorates his racing successes as it shows him both crossing the finish line and being rubbed down later.

Stubbs became so famous the Prince of Wales bought 14 of his works, two of which remain in the Royal Collection.

Susan Foister, director of collections, said : "This was the great age of racing and breeding and there were a great number of English aristocrats interested in the scientific breeding of horses."

National Gallery, London WC2 (020 7747 2885) until 25 September