Swynford was a British Thoroughbred racehorse. Bred at the 16th Lord Derby's stud in Lincolnshire, England he was sired by John O'Gaunt, a son of Isinglass, winner of the British Triple Crown in 1893. His dam was Lord Derby's foundation mare and 1896 Epsom Oaks winner Canterbury Pilgrim who also produced Chaucer, the 1927 and 1933 Leading broodmare sire in Great Britain & Ireland.

Canterbury Pilgrim (1893–1917) was a British Thoroughbred racehorse and broodmare. She showed some ability as a juvenile but failed to win a race. She won the Oaks Stakes on her first run as a three-year-old and went on to win the Liverpool Summer Cup, Park Hill Stakes and Jockey Club Cup before being retired at the end of the year. As a broodmare the best of her offspring was Swynford, a top-class racehorse who was even better as a breeding stallion. She also produced the influential sire Chaucer and several good broodmares. She has been described as "one of the most influential horses, stallion or mare, of the Twentieth Century".