Top American Thoroughbred Stallions

Not only was Man o' War one of the immortals of horse racing, he later became a top sire. Retired to stud at the age of 4 after his brilliant career, he sired 64 stakes winners. His son, War Admiral, the famous rival of Seabiscuit in 1930s America, won the Triple Crown. He didn't just sire flat racing winners -- his son Battleship won the Grand National Steeplechase at Aintree, England.

Named Horse of the Year in 1957, Bold Ruler was the first stallion whose offspring won more than $2 million in one season. That accomplishment, in 1966, was followed by his sons and daughters winning at least $1 million annually until 1970. His most famous son was Secretariat, arguably the greatest racehorse of the postwar era. Secretariat didn't reproduce his quality directly, but turns out to have excelled as a broodmare sire.

Northern Dancer won the Kentucky Derby and the Preakness, but his highest claim to fame was his potency as a sire. The grandson of the top English stallion Nearco, Northern Dancer fathered 635 foals. Of that number, an astonishing 467 won races, and of those, 123 won stakes races, according to the New York Times.

At his death in 1988, the New York Times called Raise A Native the "most influential sire of American thoroughbred stallions over the last 20 years." Although he ran only as a 2-year-old, undefeated in four races, his retirement to the breeding shed produced such colts as Alydar, Mr. Prospector and Majestic Prince, the first two also leading sires. Raise A Native's offspring included 74 stakes winners. He was the son of another top American stallion, Native Dancer.

At his peak, a breeding to Storm Cat set a mare owner back half a million dollars. This grandson of both Northern Dancer and Secretariat was the leading North American sire at the turn of the millennium. His best-known colts include Tabasco Cat and Giant's Causeway.