Yes. War Cloud was the first to compete in all three races. But, Sir Barton was the first to win all three.
Because it is the first race in the Triple Crown and if a horse wins it then there is a possibility for a Triple Crown winner.
Sir Barton
The first horse to ever win the triple crown was Sir Barton. Sir Barton was born in 1916 at the breeding farm of Madden and Gooch in Kentucky.http://triple-crown-racing.suite101.com/article.cfm/sir_barton_won_first_triple_crown
The Kentucky Derby is the first leg of the Triple Crown, a horse that wins the Kentucky Derby, The Preakness, and the Belmont Stakes becomes the Triple Crown Winner
horse racing was probably the first sport to use the term triple crown. obviously, this term is used in other sports such as baseball, but it originated from horse racing.
Secretariat won the triple crown in 1973. He was the 9th horse to do so in 25 years.
Horse racing
Yes, Man o' War was the first horse to win the prestigious Triple Crown, which includes the Kentucky Derby, Preakness Stakes, and Belmont Stakes. However, it's important to clarify that while Man o' War is often regarded as one of the greatest racehorses in history, he did not actually win the Triple Crown, as the term was formally defined after his racing career. The first horse to officially win the Triple Crown was Sir Barton in 1919.
Secretariat won in 1973.
Seattle Slew won the Triple Crown in 1977.
The horse that won the TC in 1919 was Sir Barton
Secretariat