Sovereignty not making the trip to Baltimore follows decades of debate about spacing out the Derby, Preakness and Belmont.

Thirteen horses have won the Triple Crown in American Thoroughbred racing history. Here's a look at the winners and the history of the Triple Crown:

The Triple Crown is an accomplishment that a select group of horses has achieved throughout history. When a horse wins all "jewel" races in a single season -- the Kentucky Derby, Preakness Stakes and Belmont Stakes -- it's widely regarded as one of the highest honors in all of sports.