WWE Hall of Famer and Dwayne Johnson’s father Rocky “Soul Man” Johnson died on Wednesday. He was 75.

His cause of death is not currently known.

“Soul Man” made history as the first African American world tag team champion as a member of the Soul Patrol alongside Tony Atlas. After retiring from the sport in 1991, the wrestling superstar later began training his son The Rock, who eventually became one of the biggest figures in the sport — something Johnson describes as one of his greatest achievements in his autobiography, “Soulman: The Rocky Johnson Story.” He was inducted by his son into the WWE Hall of Fame in 2008.

Johnson, born and raised in Nova Scotia, began his career in the mid 1960s as part of the National Wrestling Alliance. He quickly went on to become the first African American to win the Southern, Georgia and Florida heavyweight titles before starting his wrestling career with WWE in 1983. The wrestler had several memorable rivalries with competitors like Greg “The Hammer” Valentine, Adrian Adonis and Don Muraco.

Numerous wrestlers have shared their condolences on Twitter.

“I am so sorry to hear of the passing of the great Rocky Johnson,” Mick Foley wrote. “Always a gentleman, I always enjoyed talking with him. My deepest condolences to his family, friends, and the fans who loved him. A very sad day for wrestling.”