The event was devised by Anthony St Leger, an army officer and politician who lived near Doncaster. It was initially referred to as "A Sweepstake of 25 Guineas", and its original distance was two miles. The rules stipulated that colts and geldings were to carry 8 st, and fillies would receive an allowance of 2 lb. The inaugural running was held at Cantley Common on 24 September 1776. The first winner was an unnamed filly owned by the event's organiser, the 2nd Marquess of Rockingham. The filly was later named Allabaculia. The title St Leger Stakes was decided at a dinner party held in 1776 at the Red Lion Inn located in the Market Place, Doncaster, to discuss the following year's race. It was suggested that it should be called the Rockingham Stakes in honour of the host, the Marquess of Rockingham, but the Marquess proposed that it should be named instead after Anthony St Leger. The event was moved to its present location, Town Moor, in 1778. The race came to national prominence in 1800, when a horse called Champion registered the first Derby–St Leger double. Its length was cut to 1 mile, 6 furlongs and 193 yards in 1813, and despite some minor alterations has remained much the same ever since. The victory of West Australian in 1853 completed the first success in the Triple Crown.
Post-1900
The St Leger Stakes was closed to geldings in 1906. It was transferred to Newmarket during World War I, and the substitute event was called the September Stakes. It was cancelled in 1939 because of the outbreak of World War II, and the following year's edition was held at Thirsk in November. For the remainder of this period it was staged at Manchester, Newmarket and York. The race was switched to Ayr in 1989 after the scheduled running at Doncaster was abandoned due to subsidence. The 2006 race took place at York because its regular venue was closed for redevelopment. The St Leger Stakes has inspired a number of similar events around the world, although many are no longer restricted to three-year-olds. European variations include the Irish St. Leger, the Prix Royal-Oak, the Deutsches St. Leger and the St. Leger Italiano. Other national equivalents include the Kikuka-shō, the New Zealand St. Leger and the VRC St Leger.
John Scott – Matilda, The Colonel, Rowton, Margrave, Touchstone, Don John, Charles the Twelfth, Launcelot, Satirist, The Baron, Newminster, West Australian, Warlock, Imperieuse, Gamester, The Marquis
As the last of the classics, the race marks the end of summer in England. The popular adage "sell in May and go away, come back on St Leger Day" suggests investors should sell their shares in May and buy again after the race. The Agatha Christie novel The A.B.C. Murders has the St Leger as a plot point near the end of the novel.
