Sir Thomas (horse)
Sir Thomas (1785 – after 1790) was a British Thoroughbred racehorse. In a career that lasted from October 1787 to May 1790 he ran thirteen or fourteen times and won nine or ten races. In 1788 he became the first horse owned by a member of the British Royal Family to win the Epsom Derby, having been bought as a two-year-old by the Prince of Wales who later became King George IV. Following his win in the Derby, Sir Thomas raced in the Prince's ownership with some success until 1790.
Background
Sir Thomas was bred by Mr Dawson who owned him for his first race. Sir Thomas's sire Pontac won several races at Newmarket in 1776 and 1777, before retiring to stud. As a stallion he was first based at Richmond in Yorkshire and later moved to Brigg in Lincolnshire. Sir Thomas was the tenth of eleven foals produced by the mare Sportsmistress who had previously produced the successful racehorse and important sire Potoooooooo, by Eclipse.
Racing career
1787: two-year-old season
Sir Thomas reportedly won his only start as a two-year-old after which he was bought for 2,000 guineas by the Prince of Wales. This probably took place in 1787, although at this period Thoroughbreds had their official "birthdays" on 1 May and that Sir Thomas would have been described as a "Two-year-old" in the early part of 1788.