Since 1919, only 13 horses have won the title of Triple Crown winner by finishing first in the Kentucky Derby, Preakness Stakes and Belmont Stakes in the same year.

Sir Barton, foaled at Hamburg Place Farm in Lexington, Ky., was the first Triple Crown winner in 1919, before the phrase "Triple Crown" was even coined. He's pictured here after winning the 44th running of the Kentucky Derby at Churchill Downs in May 1919.
AP Photo