The Stubbs horse show

With his knowledge of anatomy, and without sentimentality, George Stubbs changed animal painting forever, writes Eileen Battersby

Magnificent, solitary, wary; a trace of fear in his eyes, the flaxen-maned chestnut stallion rears to ward off possible attack as much as to threaten. He could be lord of his own desert kingdom except he is well groomed and has been shod. His mood remains a mystery, his expressive beauty breathtaking.

Whistlejacket, foaled in 1749 and grandson of the legendary Godolphin Arabian, was the tetchy favourite of Charles Watson-Wentworth, the second Marquess of Rockingham, and twice British prime minister. The stallion was 13 years old, long retired from his brief racing career, and at stud when the 18th-century self-taught English master, George Stubbs, painted him in 1762.

Revered as an iconic representation of equine perfection, Whistlejacket is probably the most famous painting of a horse in Western culture, and it remains among the most popular images in the history of art. The large canvas, which depicts its majestic hero against a pale green backdrop, is otherwise empty.

Whistlejacket shares his stage with neither man nor object, not even the suggestion of a landscape. Classical, if also intriguingly modern, this life-sized sculptural portrait is the dramatic centrepiece of a glorious exhibition, Stubbs and the Horse, currently running at the National Gallery in London. For all its grandeur, it is but one spectacular example of the visionary genius of Stubbs, whose complex gifts went far beyond superlative studies of thoroughbred race horses.

Born in Liverpool in 1724, the only son of a currier, or leather worker, George Stubbs set out to be a serious artist, an elite history painter. Nothing was made easy for him. Although he attracted patrons, including the prince of Wales, the future George IV for whom he painted 14 pictures, Stubbs would never command the fees of Sir Joshua Reynolds. Nor would he enjoy the favour of the Royal Academy. Stubbs learnt all about hard work from his father, who did not want his son to be an artist. According to Robin Blake, author of the outstanding recently published biography, George Stubbs and the Wide Creation, the artist's father considered painting "as nothing but a mountebank activity".

Eventually, while lingering on his deathbed, Stubbs senior, always proud of his son's draughtsmanship, relented - advising the youth, then approaching 17, to seek out a good teacher. Stubbs was not a natural pupil and was never formally trained - his brief apprenticeship to artist Hamlet Winstanley in Warrington appears to have been more job than pupillage. Stubbs developed his drawing technique through practice and observation, not instruction.

Exactly how he learnt to paint remains unclear. Yet he became the consummate realist as well as a dedicated professional. His ambition was well served by intelligence, talent, scientific curiosity, his knowledge of anatomy, singular originality, a disciplined human sympathy and that inherited work ethic sustained by a robust constitution which endured until the day he died - on July 10th, 1806, six weeks short of his 82nd birthday.

For most of his life, and for nearly 150 years after his death, he was viewed as little more than a sporting artist, entrusted with celebrating early heroes of the turf such as Eclipse, Gimcrack, Lustre, Mambrino, Dungannon. Possibly most remarkably of all, Stubbs was 75 when he painted Hambletonian in post-race exhaustion. The artist had to sue for his fee. The huge work hangs at the National Trust property, Mount Stewart, in Co Down, and, unlike his portraits of the other horses named above, has not travelled to London for the exhibition.

In about 1950 "the ingenious Mr Stubbs" - as synonymous with horses as the much later John James Audubon is to birds - was rediscovered; his work spans the colourful world view that was Georgian England. To look at his paintings is to consider the panorama of 18th-century English social history - self-improving merchants, aristocrats, wayward royalty and the birth of horse racing can all be seen through the imagination of a man shaped by the Enlightenment.

Stubbs displayed a classical sensibility and an awareness of Edmund Burke's philosophy, whose theory of the sublime must have inspired the terrible beauty of his allegorical horse and lion series, painted between 1762 and 1788.

From the age of five, Stubbs showed a passion for drawing, and within a few years struck up a friendship with two older boys, also aspiring artists from craft-worker backgrounds. He was "scarcely eight years old" - reports fellow artist Ozias Humphry, to whom the elderly Stubbs would outline a memoir of sorts - when "he began his little studies in anatomy".

Following his spell as Winstanley's assistant, on whom he walked out, Stubbs left Warrington. Setting out as a journeyman portrait artist commissioned by self-improving merchants, he moved to Wigan and Leeds before finally arriving at York, then a medical centre and infamous for the amount of anatomical dissection being carried out. His years of drawing the bones and organs of animals from his father's tannery proved useful in dissecting and drawing the human body.

His spell in York was a significant six or seven years. In 1751 he illustrated Dr John Burton's An Essay Towards a Complete New System of Midwifery, with 18 etchings. Having been shown the technique at its most basic, he duly experimented and developed an awesome technical skill for anatomical detail that would later elevate his equestrian paintings to high art.

Although he was not a doctor, having studied anatomy, he moved on to teaching it and lecturing medical students. His interest in anatomical illustration echoed that of an earlier genius, Leonardo da Vinci. Stubbs had the talent - and the stomach - to bring his anatomical work a stage further.

Before this, he visited Rome. Although not a classical scholar, he was by instinct a classicist and recognised methodological similarities, particularly in representation and design. All of this is the vital background upon which Stubbs, who was at that time one of many struggling portrait artists, made his decision to become the finest painter of horses.

To achieve this, in 1756, he rented a barn at Horkstow, near Hull and, with a female assistant, Mary Spencer (who would be his unofficial companion for 50 years), spent 18 months dissecting horses. They were delivered to him live, and he undertook the slaughtering, with the objective of learning equine anatomy through investigating the five muscle and tissue layers down to the skeleton. It was very physical, deliberate work - like his art. Suspending the carcasses from an iron bar with pulley-like supports, he then injected the veins with liquid wax to prevent them collapsing. After he had stripped away the skin and peeled back the muscle layers, Stubbs explored the horse. Later he would recall having spent 11 weeks working on one carcass.

There is a bizarre irony in realising that such gruesome, filthy and smelly an undertaking produced a book as beautiful and as dignified as The Anatomy of the Horse. Some 22 of the drawings, including three pages from the finished original, form part of the exhibition.

The Anatomy of the Horse was the first major such work since the Bolognese Carlo Ruini's Dell'Anatomia e dell'infirmita del Cavallo had appeared in 1598. Stubbs completed all the drawings as well as the 18 finished studies by 1758. Intent on having his sketches and text printed and published, Stubbs, then 34, set off for the one place capable of guaranteeing his future - London.

Difficult as it is to believe today, his bid to secure a publisher failed. Left with no choice, he did the engraving himself - in whatever spare time he could find between working on commissions. The Anatomy of the Horse was finally published by Stubbs in 1756. His first London commission came from artist Joshua Reynolds, who needed a horse painting. One group of potential buyers who were immediately taken with Stubbs's Anatomy of the Horse drawings were the wealthy young aristocrats with country estates and horses they were proud of. One such was Charles Lennox, another Rockingham and the third Duke of Richmond. He was a committed fox hunter and racing fan, and wanted three paintings of his family hunting, shooting and being engaged by the outdoors, as recorded in The Duchess of Richmond and Lady George Lennox Watching the Duke of Richmond's Racehorses at Exercise (1759-60), which also features in the exhibition.

Stubbs spent nine months at the Goodwood estate. The duke was a science graduate, and in common with many of his horse-owning aristocratic pals, was seriously involved in breeding the thoroughbred as a scientific as much as sporting project. Another of Stubbs's commissions was Gimcrack on Newmarket Heath with a Trainer, a Stable-Lad, and a Jockey (1765), a time-shift composition in which the grey colt, is seen galloping in the distance past the winning post, well clear of the field, while in the foreground, he is being rubbed down. Stubbs painted Gimcrack several times, as the horse was to have six owners.

Dominating the third room of the exhibition is the portrait of Whistlejacket, so lifelike that its subject is believed to have spooked at it, apparently thinking another horse had arrived. The painting was purchased by the National Gallery in 1997 with the support of the Heritage Lottery Fund. When the image was flashed up on the gallery's facade, it caused a moment of national celebration.

Most of the paintings in this room are Rockingham commissions, and although the eye continually returns to the watching stallion, several magnificent works also compete for attention. There are three exquisite studies of brood mares and foals, including Mare and Foals (1762) which, with its plain background, may have been inspired by the successful use of such a daring device in Whistlejacket. This peaceful study resembles a classical frieze. Equally frieze-like is Whistlejacket and Two Other Stallions, with the Groom Simon Cobb (1762). The horses are superb, and so too is the rendering of Cobb. Stubbs paid close attention to his human subjects. He caught their expressions - his grooms, trainers and jockeys all emerge as individuals engrossed in their work.

Stubbs left no letters, no journals. He fathered at least four children but their mother appears to have slipped out of history before the arrival of Mary Spencer. Relatively little is known about him. As with JS Bach, we best arrive at a sense of his character through his methodology as an artist.

Stubbs never sentimentalises horses. He acknowledges their remoteness and their dignity. Immense pathos underlines his study, The Marquess of Rockingham's Scrub, with John Singleton Up (1762). Both jockey and horse, fellow campaigners, are at the end of their careers. Singleton has a weary demeanour. The duke presented the retired horse to his old jockey.

Before Stubbs, animal painting, however accomplished, was dismissed as secondary to history painting. He wanted to be a serious artist and looked to history, mythology, science and life. Above all, his genius was informed by instinct, a feel for the natural, the beautiful, the real and the humane.

Stubbs and the Horse runs until Sept 25 at the National Gallery, London (0044-870-9063891). George Stubbs and the Wide Creation, by Robin Blake, is published by Chatto, £25