The Iron Sheik, one of the most recognizable personalities in professional wrestling history, has died at 81 years old.

Sheik’s death was announced through a statement issued by his representatives on Wednesday morning. His cause of death was not revealed.

“Today, we gather with heavy hearts to bid farewell to a true legend, a force of nature, and an iconic figure who left an incredible mark on the world of professional wrestling,” the statement said. “It is with great sadness that we share the news of the passing of The Iron Sheik, but we also take solace in knowing that he departed this world peacefully, leaving behind a legacy that will endure for generations to come.”

Born in Iran in 1942, Sheik (real name Hossein Khosrow Ali Vaziri) was an accomplished amateur wrestler before beginning his professional career. He broke into the industry through Verne Gagne’s AWA and would go on to become one of the greatest heel wrestlers of his era.

Sheik is best known for his run in WWE (then known as the WWF), where he held the company’s world championship one time. He defeated Bob Backlund for the title in December 1983. Just one month later, Sheik would help launch the era of Hulkamania. Hulk Hogan defeated Sheik to win the WWF world championship at Madison Square Garden on January 23, 1984. Hogan would remain champion for four years as the WWF exploded in popularity.

Sheik competed at the first-ever WrestleMania in 1985, winning the WWF tag team titles with Nikolai Volkoff. Sheik and Volkoff were both enshrined into the WWE Hall of Fame in 2005.

“WWE is saddened to hear of the passing of WWE Hall of Famer The Iron Sheik, and extends its condolences to his family, friends, and fans,” WWE wrote in a statement.

Sheik and his family battled great personal tragedy when Sheik’s eldest daughter Marissa was murdered by her boyfriend in 2003. Sheik is survived by his wife Caryl, daughters Tanya and Nikki, and five grandchildren.

“The Sheik,” a documentary focused on Sheik’s life, was released in 2014.

In his later years, Sheik found revitalized fame as a pop culture personality. He made appearances on The Howard Stern Show and had a popular Twitter account with jokes ghostwritten by his management team.