abstract:Alydar (March 23, 1975, Calumet Farm – November 15, 1990) was a chestnut colt and an American Thoroughbred race horse who was most famous for finishing a close second to Affirmed in all three races of the Triple Crown of Thoroughbred Racing, a feat not achieved before or repeated since. He has been described as the best horse in the history of Thoroughbred racing never to have won a championship.