Dean Martin and Jerry Lewis angrily terminated their relationship 10 years to the day after it began, after taking the world by storm with one of the most popular comedic performances of all time.

Twenty years after their breakup, their mutual friend Frank Sinatra shocked them with an onstage reunion.

Even then, the men didn’t entirely reconcile until the burial of Martin’s son, Dean Paul Martin Jr., who died in an aircraft crash in 1987. They remained casual friends after that.

When Lewis, who died on Sunday at the age of 91, originally teamed up with Martin in 1946, their act soared to unprecedented levels of fame. Martin and Lewis became the kings of comedy on stage, television, and in film pictures, thanks in part to a boom in mass media and the country’s postwar demand for more light-hearted entertainment.

When they were on stage together, they would create a frenzy and make the audience laugh. Steve Lawrance, the vocalist, once told People:

“When these two guys got together and opened at the Copacabana, you would not believe the pandemonium that existed in that club. It just went nuts.”

Martin was originally seen by Lewis while playing in a New York City nightclub. Lewis leaped at the chance to meet Martin later, when they both performed the Havana-Madrid club on the same night in 1946, recognizing raw promise. Lewis, nine years Martin’s junior, addressed his future colleague by asking, “You workin’?” as he described in his 2005 biography, Dean and Me: A Love Story. They became buddies and began experimenting with routines outside of work hours.

After messing about with pieces at the club after hours, Lewis persuaded the owner of the 500 Club in Atlantic City to hire Martin after a vocalist dropped out of a set. That night, they put on their debut show together, performing the same acts they had prepared at the Havana-Madrid.

The concert was a tremendous hit, and it laid the groundwork for Martin and Lewis. Lewis would play the clown in the performance, causing mayhem onstage as Martin performed his routine calmly and collectedly. The relationship was later described by Lewis as “sexy and slaptick.” “I don’t think we would have ever been heard of without the other,” he told PEOPLE in 1995.

“When Jerry and Dean started, it was like an explosion,” singer Steve Lawrence told PEOPLE. “When these two guys got together and opened at the Copacabana, you would not believe the pandemonium that existed in that club. It just went nuts, and you couldn’t get in the joint after that. They broke every record in the house.”

Dean and Martin’s performance also had a sensuality appeal that had never been seen in comedy before. “This was the first time a comedy act looked like this,” Lawrence said. “They were very attractive-looking guys, and before that you had duos like Laurel and Hardy and Abbot and Costello and Olson and Johnson. Then Martin and Lewis came along and they were just so different than any of those guys.”

The juxtaposition of two distinct identities has drew the attention of Paramount officials. “My Friend Irma,” their debut picture, was a great hit. “The Stooge,” “Living It Up,” “Artists and Models,” and “Hollywood or Bust” were among the numerous films in which the two collaborated.

According to The Hollywood Reporter, resentment built between the pals at the end, and they fought regularly.

According to USA Today, their issues grew worse during the marketing of their 1954 picture Living It Up, when Look magazine clipped Martin out of a shot. While filming their final film, Hollywood or Bust, the two entirely disregarded each other. Lewis subsequently admitted to having ego issues, identifying himself as a “bully” during this time in his memoir. Martin and Lewis did one final concert together at the Copacabana in New York City, 10 years after their debut routine, as a goodbye.

During the premiere of their 1954 picture “Living It Up,” their feud became public knowledge.

Martin began to believe Lewis had too much influence over their work, and he discussed returning to his solo career. Lewis, who still admired Martin in many respects, felt betrayed, and the two didn’t communicate for a long time.

Jerry Lewis was a workaholic, but Dean Martin was known for relaxing and enjoying his free time.

A lot of folks thought the comic performance was one-sided, with Jerry carrying the duo.

People also believe the duo broke up because of their spouses. Dean’s second wife, Jeanne, apparently had a strained relationship with Jerry, as did Dean and Jerry’s wife, Patti.

According to Vanity Fair, Sinatra “completely caught Lewis off guard” when he planned their surprise reunion for Lewis’s annual Labor Day gala in 1976. Martin, who had been hiding in telethon co-host Ed McMahon’s dressing room, walked across the stage and hugged and kissed his former partner, earning a standing ovation from the crowd. Lewis, on the other hand, was not pleased: “You son of a bitch,” he said to Sinatra.

“So, how ya been?” Lewis asks.

Martin comments, “You know, it seems like we haven’t seen each other in 20 years.”

“Well, you know, there was all those rumors about our breaking up—and then when I started the show and you weren’t here, I believed it.”

Martin’s daughter, Deana, told Vanity Fair last year, “They loved each other. There was something amazing about Dad. He was nice and sweet and kind to everyone, and he would let things go. But when he had it up to here, he’d had it up to here. There was no fight or any yelling. He would just be done.”

When Dean Paul Martin Jr., Martin’s oldest son, died in an aircraft crash in 1987, Lewis attended the burial and publicly reconciled with his former stage partner. They were in touch on and off until Martin’s death in 1995.

Lewis began speaking more fondly of Martin in public after his death, even taking responsibility for their acrimonious breakup. In 2002, Lewis told PEOPLE, “I broke up the act. Dean hurt desperately. And I felt guilty of not seeing it sooner,” Lewis claimed, despite Martin’s casual demeanor over the years.