Bold Ruler was a famous American Thoroughbred racehorse, born in 1954. He is best known for his impressive racing career, which included winning the prestigious Kentucky Derby in 1957. His speed and stamina made him a standout competitor on the racetrack. After retiring from racing, Bold Ruler became a successful sire, producing many notable offspring, including the legendary Secretariat. His influence on the breed is significant, as he is recognized for passing on desirable traits to his progeny, solidifying his legacy in horse racing history.