It is generally understood that the race later known as the St Leger, a level-weights race for three-year-olds – youngsters by the prevailing standards, when horses were rarely run before four and were thought to peak at five or six – was devised by a Colonel of that name.
Racing at Doncaster had been going on since 1600 if not before. Colonel – later Major-General – Anthony St Leger, who lived at nearby Warmsworth Hall, was dismayed at the trough into which the races had sunk. He was descended from Irish aristocracy, married a Yorkshirewoman and served as MP for Grimsby while not pursuing his career in the Army and managing his estates at Park Hill near the South Yorkshire-Nottinghamshire border.
In 1776 he set up a meeting of the local great and good to discuss what could be done. The new race, a sweepstakes, was instigated and seemed to work.
In 1778, at a similar gathering at Doncaster’s premier inn, the Red Lion, the race was dignified with a name. Some thought that it should be called after the noblest figure in the room, the 2nd Marquis of Rockingham, but he courteously deflected the honour onto St Leger, whose idea it was.
Unhelpfully, Anthony’s nephew John Hayes “Handsome Jack” St Leger was also a colonel and an MP and he inherited the Park Hill estate later. His portrait was painted by Gainsborough and Reynolds. This has confused many historians, but not Tony Barber, from whose magnificent 2015 book The St Leger I take this information. Anthony can safely be regarded as the founder.
Barber explains that the identity of the winning horse in 1776 and its jockey are also subject to confusion, but you will have to get his book to find out more.