RUN in a blinding blizzard, a horse race at Richmond in 1615 ended in confusion and a row over who had won. Two wealthy racegoers chose to commemorate the event by presenting a silver tankard to the town. Dubbed the "snow tankard" it was inscribed: "The gift of Sir Mark Millbank, Bart, and John Hutton, Sen, Esq, to the Corporation after a disputed race in the great snow at Easter."

The "great snow race" provides a vivid moment in the history of racing in North Yorkshire. But it pales against the main theme: "The Thoroughbred horse which is the basis of the worldwide racing industry in over 50 countries had its origins in northern Yorkshire and the Tees valley... Horses now raced at Longchamps, Melbourne, Happy Valley in Hong Kong and Hollywood Park in Los Angles, all had their ancestors in this northern part of England."

This is the arresting opening to a book that tells the extraordinary tale. Who, from this "northern part of England," would not want to read on? Besides, curiosity has already been aroused by the banner under which author David Wilkinson, of Old Byland, near Helmsley, presents his self-published book: Old Bald Peg Publications.

Old Bald Peg turns out to have been a horse born on the Duke of Buckingham's Helmsley estate in about 1635. Its distinction, David reveals, is that it "can be found in the pedigree of many (if not most) modern racehorses." A daughter of the mare produced Spanker "the fastest racehorse of the day at Newmarket." And the father of this champion was another North Yorkshire horse, Darcy's Yellow Turk, from the stud of the James Darcy, of Sedbury Park, near Richmond.

Darcy supplied Charles II with 12 colts that so impressed the monarch he appointed Darcy master of the Royal Stud. "In effect," notes David, "Sedbury became the Royal Racing Stud and was the stable of the so-called Royal Mares."

North Yorkshire's top role went back further. When racing began to emerge as a sport in the sixteenth century - supplanting jousting among others - racehorses, known as running horses, were small Galloway ponies, generally under 14 hands. Most racing took place on high ground that offered good turf which didn't dry out too much in summer.

As David explains, North Yorkshire, with mineral soils that fostered strong bone development, a long grass-growing season yet moderate rainfall, open moors for training, and horse-expertise bred by many wars, was "ideal" for both rearing and racing horses.

Still in use for training, the famous Hambleton gallops at Sutton Bank emerged as "the most important aristocratic rural meeting in Yorkshire." Its three miles of turf formed "a natural racetrack, probably the best in the country." Now seeming out of the way, it was convenient for training grounds at Malton, Richmond, Middleham and Helmsley. And the old Drove Road, directly beside the track, offered relatively easy access for many racegoers.

The Hambleton winning post was an obelisk on which was set each year a new Gold Cup donated by the monarch. But Gatherley Moor, north of Richmond, scene of that "great snow race," was another leading course. It hosted the Richmond races, later run at North Moor then, from 1765, on Whitecliffe, where the ruined John Carr stand still survives.

The importance of the course and training gallops was mirrored in their exclusion from nineteenth century enclosure. Also applied to Middleham Low Moor, this exemption has allowed training in both places to continue to this day.

Northallerton held a three-day meeting on a course whose grandstand stood on the site of the present County Hall. Stokesley, Malton, Coatham, Boroughbridge and Scarborough were also racing venues, as were the surviving quartet of Ripon, Thirsk, Redcar and, the big one, York. In 1633, Charles I attended a York meeting on Acomb Moor, predecessor of a course at Rawcliffe Ings, itself replaced by the Knavesmire in 1731.

Early races were usually run over four or five miles. With heats preceding the main event, an eventual winner often would have run 16 miles in the afternoon. Purists were appalled when, to fit in more races, mainly to serve the booming gambling industry, races were shortened and contested by younger horses. York staged the first race for three-year-olds in 1770.

But both speed and stamina improved when Yorkshire's own foundation stock, produced especially by the Darcys in crossing their horses with those of the Duke of Buckingham, was further crossed with Arab stallions.

The pioneer was a horse called Byerley Turk, brought to Britain in 1687 by a Capt Robert Byerley, of Middridge, Co Durham, later Goldsborough Hall, Knaresborough. Placed on stud at Streatlam, home of John Bowes, founder of the eponymous Museum, he sired an important mare - literally named The Byerley Turk Mare - whose line penetrates deep into French breeding stock.

Another early import, sent by Thomas Darley, British consul in Aleppo, Syria, to his father's estate at Aldby Park, Buttercrambe, Malton, was the Darley Arabian.

His offspring, Bully Rock, owned by Thomas Metcalfe, of Porch House, Northallerton, became, reports David, "one of the first English stallions imported into Virginia as the foundation stock of North America."

More illustrious descendants included Marske, an exceptional stallion bred by John Hutton, of Marske Hall, Swaledale. Out of his union with a mare bred by Robert Eden, of Windlestone, near Darlington, came Eclipse - "probably the greatest racehorse of all time," says David. And certainly one with an impeccable Northern pedigree.

The genesis of the Thoroughbred, the Arabian crossbreeding, spelled the end for Galloway racing, abandoned at York in 1740. Even so, "the North bred most of the horses raced in the country until about 1750" says David, whose 88-page book, well designed and illustrated, stems from his MA thesis at York University. "Most of the Newmarket runners were raised in Yorkshire and surrounding areas."

But the North's influence waned as economic power shifted to the south. Ironically, racing at Newmarket, now synonymous with the sport, was started at the suggestion of the Duke of Buckingham - before he acquired the Helmsley estate by marriage.

Most small courses closed when a £50 minimum prize was set in 1740. Better-placed for the social life that increasingly accompanied racing, York displaced Hambleton, which closed in 1775, though a hopeless revival was attempted in 1811.

Partly because it was bypassed by main railways, Richmond, which had shared Hambleton's former Gold Cup with York on an alternate basis, succumbed in 1891.

But, apart from that remarkable bloodstock, the Yorkshire heyday had produced some notable firsts. The first race documented on a racing calendar, and the first recorded ride by a jockey were both run at Rawcliffe Ings in 1709. In 1576, Richmond was ahead of its time in suggesting a cup as a trophy. A bell was the usual prize.

Yorkshire also pioneered the concept of the public trainer - that is, not employed by one owner. Malton's John Scott (1794-1871) became, says David, "the first great public trainer." Between 1832 and 1862, he produced six Derby winners and 16 St Leger winners at his Whitewall stables.

But gradually yet inevitably the best bloodstock became concentrated in racing's new centre of gravity - the south. With only a single Derby victory since 1869 - the Middleham (Matt Peacock) trained Dante in 1945 - the North became a lame (if game) runner-up, its crucial foundation role largely unknown except to devotees of racing history.

Despite its academic origin and dry title, David Wilkinson's book, which features profiles of major figures, horses and courses, set into a wider narrative, is the accessible account needed to lift an amazing truth out of its present obscurity: Thoroughbred Racing - Born in Yorkshire.

* Early Horse Racing in Yorkshire and the Origins of the Thoroughbred by David Wilkinson (Old Bald Peg Publications, West View, Old Byland, Yorkshire, YO62 5LG, softback, £9.95)