Racing juveniles
Prior to 1727 the only horses which were allowed to race were 5-year-olds and upwards, especially as the norm was for races over extended distances up to 8 miles, and, with races run in heats, this meant some horses were completing upwards of 20 miles in a day. In 1727 4-year-olds were introduced into the programme, although it was not until 1756 that 3-year-olds began racing. The debate then began about whether to lower the age barrier even further. Even as early as 1770 the Stewards, notably Sir Charles Bunbury, Lord Bolingbroke and Jenison Shafto put their toe in the water and produced an order regarding 'Verification of age of racehorses', which included a reference to 2-year-olds.

The earliest record of a two-year-old racing at Newmarket was on 26th October 1769 over the last 6 furlongs of the Rowley Mile, although it was very much an experimental race with the two-year-old Gibscutski taking on the 6-year-old Stilts in receipt of 3 stone.
Thursday 26th October 1769 £200 Match over 6 furlongs
1. GIBSCUTSKI, 2-y-o by Gibson’s Arabian 6st owned by Mr C Blake
2. STILTS, bay mare 9st owned by Mr Ogilvy

In 1773 Sir Charles encouraged the Stewards to promote the Grosvenor Plate weight for age race over 2 miles, with 2-y-olds set to carry 4st 8lbs, 3-y-olds to carry 6st 7lbs and increased weights for horses of 4-y-o and above. There were no 2-year-old takers, although in November 1773 there was a further Match involving a 2-year-old against a 4-year-old over 4 miles of the Beacon Course.
Thursday 4th November 1773 over 4 miles of the Beacon Course
1. BABY, grey 2-year-old carrying a feather owned by Sir Charles Sedley
2. CHESTERTON, 4-year-old carrying 11st owned by Mr Charles James Fox

It was a further 2 years before the first race entirely involving 2-year-olds, both carrying 8st, albeit a Match over the Rowley Mile.
Saturday 21st October 1775 for 200 Guineas over the Rowley Mile
1. RISQUE, by Metaphuscian owned by Mr Walker
2. FRONTINO, bay colt owned by Mr Jennings

A year later the first two-year-old race over the first 4 furlongs of the Rowley Mile was staged on 29th October 1776.
Tuesday 29th October 1776
50 Guineas Sweepstake for 2-y-o over first 4 furlongs of Rowley Mile
1. ARABIAN grey colt 7st 10lbs owned by Mr Richard Vernon
2. PETWORTH, bay colt 7st 10lbs owned by Mr Ogilvy
3. MISS GRANTHAM, bay filly 7st 10lbs owned by Miss Grantham

Although it was an inauspicious start to 2-year-old racing at Newmarket, the Jockey Club persisted, but it was a decade later before the inaugural July Stakes, the oldest surviving event for two-year-olds, was run over 6 furlongs in 1786. Whilst it was no surprise that colts carried 8st 2lbs and fillies 8st, a surprise condition for the early July Stakes was that horses sired by Eclipse or Highflyer had to carry an additional 3lbs.
Monday 10th July 1786
July Stakes 50 Guineas over 6 furlongs
1. BULLFINCH, chestnut colt owned by Lord Clermont
2. BUSTLER, chestnut colt owned by Mr Richard Vernon
3. PRIZEFIGHTER, bay colt owned by Duke of Grafton
4. MAMBRINO filly owned by Lord Grosvenor
5. PICQUET, bay colt owned by HRH Prince of Wales
6. SHARK colt owned by HRH Prince of Wales
7. IMPERATOR, bay filly owned by Lord Clermont
8. CERES sister owned by Lord Grosvenor

Although the July Stakes became firmly established in the Racing Calendar, and has stood the test of time for over 2 centuries, there was a big difference in opinion, even within the Jockey Club, about whether the racing of juveniles was good for the progress of the thoroughbred breed, or whether too much strain was being put on such young horses.

While opinion was split almost 50-50 over 2-year-old racing, no one today questions the logic of racing horses at two, but equally no one would support the idea of racing yearlings, yet for some unknown reason, Sir Charles Bunbury and fellow Jockey Club Members promoted it. To his credit Sir Charles Bunbury never allowed one of his yearlings to contest a race.