Keysoe (1916–1929) was a British
Thoroughbred
The Thoroughbred is a horse breed best known for its use in horse racing. Although the word ''thoroughbred'' is sometimes used to refer to any breed of purebred horse, it technically refers only to the Thoroughbred breed. Thoroughbreds are c ...
racehorse and
broodmare
A mare is an adult female horse or other equine. In most cases, a mare is a female horse over the age of three, and a filly is a female horse three and younger. In Thoroughbred horse racing, a mare is defined as a female horse more than four ...
. Bred and owned by the
17th Earl of Derby
Edward George Villiers Stanley, 17th Earl of Derby, (4 April 1865 – 4 February 1948), styled Mr Edward Stanley until 1886, then The Hon Edward Stanley and then Lord Stanley from 1893 to 1908, was a British soldier, Conservative politician, d ...
she was the product of a mating between two St Leger winners and won the race herself in 1919. She was unraced as a juvenile but developed into a top-class stayer at three, winning the Gratwicke Stakes and the
Nassau Stakes at
Goodwood Racecourse
Goodwood Racecourse is a horse-racing track five miles north of Chichester, West Sussex, in England controlled by the family of the Duke of Richmond, whose seat is nearby Goodwood House. It hosts the annual Glorious Goodwood meeting in lat ...
before taking the St Leger and later winning the Newmarket Oaks. She failed to win as a four-year-old in 1920 although she was placed in all of her races. After her retirement from racing, she had considerable success as a broodmare despite producing very few foals.
Background
Keysoe was a brown mare reportedly standing 17
hands high bred in England by her owner
Edward Stanley, 17th Earl of Derby. During her racing career she was trained by
George Lambton
George Lambton (23 December 1860 – 23 July 1945) was a British thoroughbred racehorse trainer. He was British flat racing Champion Trainer in the 1906, 1911 and 1912 seasons.
Early life
The Honourable George Lambton was born in London on 23 ...
at the Stanley House stable near
Newmarket, Suffolk
Newmarket is a market town and civil parish in the West Suffolk district of Suffolk, England. Located (14 miles) west of Bury St Edmunds and (14 miles) northeast of Cambridge. It is considered the birthplace and global centre of thoroughbred hor ...
.
Her sire
Swynford
Swynford (January 1907 – 18 May 1928) was a British Thoroughbred horse racing, racehorse. Bred at the Frederick Stanley, 16th Earl of Derby, 16th Lord Derby's stud in Lincolnshire, England he was sired by John O'Gaunt (horse), John O'Gaunt, a so ...
was an outstanding racehorse who won the St Leger in 1910 and the
Eclipse Stakes
The Eclipse Stakes is a Group races, Group 1 Flat racing, flat Horse racing, horse race in Great Britain open to horses aged three years or older. It is run at Sandown P ...
in the following year. He was even better as a breeding stallion with his other offspring including
Blandford,