Sun Stream  Sun Stream (1942 – January 1959) was a British Thoroughbred racehorse and broodmare, best known for winning two Classics in 1945. The filly won five times from seven races in a track career which lasted from spring 1944 until June 1945. As a two-year-old in 1944 she won three races including the Queen Mary Stakes. After being beaten on her three-year-old debut she won the 1000 Guineas over one mile at Newmarket and a substitute Oaks over one and a half miles at the same course a month later. After her second classic win she was retired to stud, where her record as a broodmare was disappointing. Sun Stream was a chestnut mare with a white blaze and white hind feet. She was bred, like both her parents by her owner Edward Stanley, 17th Earl of Derby, the seven-time British flat racing Champion Owner. She was sired by Hyperion, who won The Derby and the St Leger Stakes for Lord Derby in 1933 and went on to become an internationally significant sire: Sun Stream's successes enabled Hyperion to claim the fourth of his six sires' championships in 1945. Sun Stream's dam, Drift, won four races including the Atalanta Stakes and became a successful broodmare, producing the 1000 Guineas winner Tideway and Heliopolis, a full brother to Sun Stream who was twice Leading sire in North America. Lord Derby sent the filly to his private trainer Walter Earl at his Stanley House stable in Newmarket, Suffolk. Sun Stream's racing career took place during World War II during which horse racing in Britain was subject to many restrictions. Several major racecourses, including Epsom, Ascot and Doncaster, were closed for the duration of the conflict, either for safety reasons, or because they were being used by the military. Many important races were rescheduled to new dates and venues, often at short notice, and all five of the Classics were run at Newmarket. As a two-year-old in 1944, Sun Stream was among the best of her generation. She won the Bedford Stakes over five furlongs at Newmarket in spring and then moved up in class for the Queen Mary Stakes in June. The race, traditionally part of the Royal Ascot meeting, was run at Newmarket from 1941 to 1944. Ridden by Harry Wragg, she won the race at odds of 100/30. In autumn, Sun Stream ran in the six furlong Cheveley Park Stakes, Britain's most prestigious race for two-year-old fillies.