Canadian–American professional wrestler Pat Patterson passed away Wednesday at the age of 79, according to World Wrestling Entertainment (WWE).

He died of cancer at a Miami, Florida hospital.

The entertainment company said in a statement, “WWE is saddened to learn that Pat Patterson has passed away at the age of 79. WWE extends its condolences to Patterson’s family and friends.”

Patterson started his career in 1958 as the first openly gay wrestling star. He was a trailblazer in the world of wrestling. He openly expressed about being a gay wrestler in his autobiography “Accepted: How the First Gay Superstar Changed WWE.”

He was best known for his battles with Sgt. Slaughter. WWE said, “He also had a number of firsts, which included the first Intercontinental Championship.”

Former wrestler and actor Dwayne “The Rock” Johnson paid tribute to Patterson in an Instagram post.

Johnson wrote, “RIP Pat. You’ll be missed. Rough phone calls to get this morning to tell me, our dear family member, Pat Patterson who was my pro wrestling mentor and father figure has passed away.”

“Love you, Pat. And thank you,” he added. “I’ll see you down the road.”

Even after retiring from the ring, Patterson continued to work for WWE. He worked as a color commentator before retiring from the booth in 1984, WWE said.

Patterson is credited by WWE for creating the format for the first Royal Rumble in 1988. WWE’s Royal Rumble is a signature event in which participants enter at timed intervals in a royal battle. Born on January 19, 1941, in Canada, Patterson was inducted into the WWE Hall of Fame in 1996 by fellow wrestler Bret Hart.