Conversation so far:
Was Affirmed the favorite in the Kentucky Derby?
Alydar was made the 6-5 favorite for Kentucky Derby, with Affirmed the second choice at 9-5.
Was the 1978 Kentucky Derby with Affirmed a close race?
Affirmed won the Kentucky Derby by 1 1⁄2 lengths.
How much did Affirmed win the Preakness by?
Affirmed held a short lead entering the stretch and held it to defeat Alydar by a neck.
Was the 1978 Belmont with Affirmed a close race as well?
Affirmed rallied in the final stride to win by a nose.
Does the Triple Crown happen often?
The Triple Crown, is a title awarded to a three-year-old Thoroughbred horse who wins the Kentucky Derby, Preakness Stakes, and Belmont Stakes. This can theoretically occur annually.

Question: Who was the last horse to win before Affirmed?
Self-contained rewrite: Who was the last horse to win the Triple Crown before Affirmed?