Tony Mendez, the Real-Life Spy Who Inspired Ben Affleck's Argo, Dies at 78

Tony Mendez, a spy best known for rescuing six American diplomats during the 1979-1981 Iran hostage crisis  — which was the subject of the 2012 film Argo — has passed away. He was 78.

Mendez, who suffered from Parkinson’s disease, died Saturday at an assisted living facility in Frederick, Maryland, a spokesperson for the International Spy Museum, of which Mendez was a founding member, confirmed to PEOPLE.

Christy Fletcher, his literary manager, also shared a statement from his family, which said Mendez had been living with Parkinson’s for over 10 years.

“He was surrounded with love from his family and will be sorely missed,” the family statement reads. “The last thing he and his wife Jonna Mendez did was get their new book to the publisher and he died felling he had completed writing the stories that he wanted to be told.”

“I was honored to work with Tony Mendez for twenty years and his loving wife Jonna,” Fletcher wrote on Twitter alongside the statement. “This is a crushing loss for his family, friends and our world. I will miss him very very much.”

Tony and Jonna, both of who worked in the CIA, are the authors of The Moscow Rules: The Secret CIA Tactics that Helped America Win the Cold War, which is scheduled to be published May 21.

Chris Costa, the executive director of the International Spy Museum, also mourned the loss of the “legendary intelligence officer.”

“We are deeply saddened to hear of the passing of our founding advisory board member, Tony Mendez. He was a legendary intelligence officer and true friend of the Museum. He will be missed,” Costa says in a statement obtained by PEOPLE.

Mendez’s work in the Iran hostage crisis was immortalized in the 2012 film Argo. Ben Affleck directed Argo and portrayed Mendez in the film.

Argo won three Academy Awards, including Best Picture.

In response to the news of Mendez’s death, Affleck paid tribute to the “true American hero.”

“He was a man of extraordinary grace, decency, humility and kindness. He never sought the spotlight for his actions, he merely sought to serve his country,” Affleck wrote on Twitter. “I’m so proud to have worked for him and to have told one of his stories. #RIPTonyMendez”

Mendez, who joined the CIA in 1965, began his career by creating counterfeit currency and forging signatures, according to The Hollywood Reporter.

By 1979, Mendez was the head of the CIA’s authentication branch, which specialized in sneaking people out of foreign countries, as well as creating fake identities, according to CNN.

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That expertise came in handy during the Iran hostage crisis, when militants stormed the U.S. Embassy, capturing 66 people. Mendez was brought in to help rescue six American diplomats who managed to escape to the Canadian Embassy.

In order to orchestrate the escape, Mendez had the diplomats pose as a Canadian film crew scouting for locations for a science-fiction film called Argo.

The mission remained classified until 1997, according to THR.

CNN reported that Mendez met Jonna, his second wife, while working in Russia in the 1980s.