|Breeder||William Haggin Perry|
|Owner||William Haggin Perry|
|Trainer||James W. Maloney|
|Boldnesian is a thoroughbred racehorse out of Alanesian by Bold Ruler. He was born around 1963 in the United States, and was bred by William Haggin Perry.|
|Santa Anita Derby (1966)|
|Horse (Equus ferus caballus)|
Boldnesian (1963–1975) was an American Thoroughbred racehorse best known in racing for winning the 1966 Santa Anita Derby and as a sire. Scheduled to run in the Kentucky Derby, Boldnesian's racing career was cut short by an operation after bone chips were discovered following his win in the Santa Anita Derby. 
At stud, Boldnesian notably sired Canadian Horse Racing Hall of Fame inductee Bold Ruckus and Bold Reasoning who in turn sired the 1977 U.S. Triple Crown winner Seattle Slew. Boldnesian was discovered to have carried the large-heart gene.