Shawn Michaels and Bret Hart have been rivals from their tag team days itself with Bret as part of the team The Hart Foundation and Shawn as part of The Rockers. At one point, The Rockers had even won the World Tag Team title from The Hart Foundation.
But the two became intense rivals around the time of Wrestlemania 12 in 1996. Bret was the reigning WWF champion. The match was stipulated to be a 60-minute Iron Man Match, where the man with the most submissions or pins becomes the winner. After 60 minutes of high intensity, the match ended 0-0.
But WWF President Gorilla Monsoon entered the ring and ordered the match to continue under sudden death rules. Michaels won the match and the title shortly thereafter. After the match, Shawn Michaels is alleged to have told The Hitman to “get the f**k out of my ring,” and the seeds for a bitter and personal rivalry were sown.
After Wrestlemania 12, Bret took some time off and during that time he was offered a big contract in the WCW. But out of loyalty toward WWF, Bret chose to stay back and sign a 20-year deal with them. Shawn was widely believed to drop his title to Bret at Wrestlemania 13; instead, he vacated the title just a few months before Wrestlemania 13 in his infamous "I lost my smile" speech.
He claimed that his doctor had told him that his knee injury would be career-ending. Bret Hart, on the other hand felt that he was faking it, as Shawn had always said that he wouldn’t do any more jobs for anyone in the territory. Bret went on to win the title again by winning the Fatal Four Way match involving Austin, Vader, the Undertaker, and himself.