Robin Williams had a larger-than-life personality. On screen and on stage, he embodied what he referred to as “hyper-comedy.” Offscreen, he was involved in humanitarian causes and raised three children—Zak, Zelda, and Cody. Since his untimely death on August 11, 2014, HBO has released the documentary Robin Williams: Come Inside My Mind, directed by Marina Zenovich, which chronicles his rise on the stand-up comedy scenes during the 1970s, to his more dramatic roles in the 1980s and ‘90s in award-winning films like Dead Poets Society; Good Morning, Vietnam; Awakenings; The Fisher King; and Good Will Hunting. In 2018, a mural with his face on it went up in Chicago, Williams’s hometown; that same year, journalist Dave Iztkoff published the book Robin.

July 21, 2021 would’ve been Williams’ 70th birthday. To celebrate, here are some things you might not have known about the iconic funnyman.

1. Robin Williams got his start in comedy at a church.

Kevork Djansezian/Getty Images for PCA

After leaving Juilliard, Robin Williams found himself back in his hometown of San Francisco, but he couldn’t find work as an actor. Then he saw something for a comedy workshop in a church and decided to give it a shot. “So I went to this workshop in the basement of a Lutheran church, and it was stand-up comedy, so you don’t get to improvise with others, but I started off doing, ostensibly, it was just like improvising but solo," he told NPR. "And then I started to realize, ‘Oh.’ [I started] building an act from there."

2. Robin Williams formed a friendship with Koko the gorilla.

In 2001, Williams visited Koko the gorilla, who passed away in June, at The Gorilla Foundation in Northern California. Her caregivers had shown her one of his movies, and she seemed to recognize him. Koko repeatedly signed for Williams to tickle her. “We shared something extraordinary: laughter,” Williams said of the encounter. On the day Williams died, The Foundation shared the news with Koko and reported that she fell into sadness.

3. Robin Williams spent some time working as a mime in Central Park.

In 1974, photographer Daniel Sorine captured photos of two mimes in New York's Central Park. As it turned out, one of the mimes was Williams, who was attending Juilliard at the time. “What attracted me to Robin Williams and his fellow mime, Todd Oppenheimer, was an unusual amount of intensity, personality, and physical fluidity,” Sorine said. In 1991, Williams revisited the craft by playing Mime Jerry in Bobcat Goldthwait’s film Shakes the Clown. In the movie, Williams hilariously leads a how-to class in mime.

4. Robin Williams tried to get Lydia from Mrs. Doubtfire back in school.

As a teen, Lisa Jakub played Robin Williams’s daughter Lydia Hillard in Mrs. Doubtfire. “When I was 14 years old, I went on location to film Mrs. Doubtfire for five months, and my high school was not happy,” Jakub wrote on her blog. “My job meant an increased workload for teachers, and they were not equipped to handle a ‘non-traditional’ student. So, during filming, they kicked me out.”

Sensing Jakub’s distress over the situation, Williams typed a letter and sent it to her school. “A student of her caliber and talent should be encouraged to go out in the world and learn through her work,” he wrote. “She should also be encouraged to return to the classroom when she’s done to share those experiences and motivate her classmates to soar to their own higher achievements … she is an asset to any classroom.”

Apparently, the school framed the letter but didn’t allow Jakub to return. “But here’s what matters from that story—Robin stood up for me,” Jakub wrote. “I was only 14, but I had already seen that I was in an industry that was full of back-stabbing. And it was entirely clear that Robin had my back.”

5. Robin Williams wasn’t producers' first choice to play Mork on Mork & Mindy.

Anson Williams, Marion Ross, and Don Most told The Hallmark Channel that a different actor was originally hired to play Mork for the February 1978 Happy Days episode “My Favorite Orkan,” which introduced the alien character to the world. “Mork & Mindy was like the worst script in the history of Happy Days. It was unreadable, it was so bad,” Anson Williams said. “So they hire some guy for Mork—bad actor, bad part.” The actor quit, and producer Garry Marshall came to the set and asked: “Does anyone know a funny Martian?” They hired Williams to play Mork, and from September 1978 to May 1982, Williams co-headlined the spinoff Mork & Mindy for four seasons.

6. Robin Williams “risked” a role in an Off-Broadway play.

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In 1988, Williams made his professional stage debut as Estragon in the Mike Nichols-directed Waiting for Godot, which also starred Steve Martin and F. Murray Abraham. The play was held off-Broadway at Mitzi E. Newhouse Theater at Lincoln Center. The New York Times asked Williams if he felt the show was a career risk, and he responded with: “Risk! Of never working on the stage again! Oh, no! You’re ruined! It’s like you're ruined socially in Tustin,” a town in Orange County, California. “If there’s risk, you can’t think about it,” he said, “or you’ll never be able to do the play.”

Williams had to restrain himself and not improvise during his performance. “You can do physical things,” he said, “but you don’t ad lib [Samuel] Beckett, just like you don’t riff Beethoven.” In 1996, Nichols and Williams once again worked together, this time in the movie The Birdcage.

7. Robin Williams ushered in the era of celebrity voice acting.

The 1992 success of Aladdin, in which Williams voiced Genie, led to more celebrities voicing animated characters. According to a 2011 article in The Atlantic, “Less than 20 years ago, voice acting was almost exclusively the realm of voice actors—people specifically trained to provide voices for animated characters. As it turns out, the rise of the celebrity voice actor can be traced to a single film: Disney’s 1992 breakout animated hit Aladdin.” Since then, big names have attached themselves to animated films, from The Lion King to Toy Story to Shrek. Williams continued to do voice acting in animated films, including Aladdin and the King of Thieves, Happy Feet, and Happy Feet 2.

8. Robin Williams forgot to thank his mother during his 1998 Oscar speech.

In March 1998, Williams won a Best Supporting Actor Oscar for his performance as Sean Maguire in Good Will Hunting. In 2011, Williams appeared on The Graham Norton Show, and Norton asked him what it was like to win the award. “For a week it was like, ‘Hey congratulations! Good Will Hunting, way to go,'” Williams said. “Two weeks later: ‘Hey, Mork.’”

Then Williams mentioned how his speech accidentally left out one of the most important people in his life. “I forgot to thank my mother and she was in the audience,” he said. “Even the therapist went, ‘Get out!’ That was rough for the next few years. [Mom voice] ‘You came through here [points to his pants]! How’s the award?’”

9. Robin Williams comforted Steven Spielberg during the filming of Schindler’s List.

At this year’s 25th anniversary screening of Schindler’s List, held at the Tribeca Film Festival, director Steven Spielberg shared that Williams—who played Peter Pan in Spielberg’s Hook—would call him and make him laugh. “Robin knew what I was going through, and once a week, Robin would call me on schedule and he would do 15 minutes of stand-up on the phone,” Spielberg said. “I would laugh hysterically, because I had to release so much.”

10. Robin Williams helped Ethan Hawke get an agent.

During a June 2018 appearance on The Graham Norton Show, Ethan Hawke recalled how, while working on Dead Poets Society, Williams was hard on him. “I really wanted to be a serious actor,” Hawke said. “I really wanted to be in character, and I really didn’t want to laugh. The more I didn’t laugh, the more insane [Williams] got. He would make fun of me. ‘Oh this one doesn't want to laugh.’ And the more smoke would come out of my ears. He didn’t understand I was trying to do a good job.” Hawke had assumed Williams hated him during filming.

After filming ended, Hawke went back to school, but he received a surprising phone call. It was from Williams’s agent, who—at Williams's suggestion—wanted to sign Hawke. Hawke said he still has the same agent today.

11. Robin Williams was almost cast in Midnight Run.

In February 1988, Williams told Rolling Stone how he sometimes still had to audition for roles. “I read for a movie with [Robert] De Niro, [Midnight Run], to be directed by Marty Brest,” Williams said. “I met with them three or four times, and it got real close, it was almost there, and then they went with somebody else. The character was supposed to be an accountant for the Mafia. Charles Grodin got the part. I was craving it. I thought, ‘I can be as funny,’ but they wanted someone obviously more in type. And in the end, he was better for it. But it was rough for me. I had to remind myself, ‘Okay, come on, you’ve got other things.’”

In July 1988, Universal released Midnight Run. Just two years later, Williams finally worked with De Niro, on Awakenings.

12. Billy Crystal and Robin Williams used to talk on the phone for hours.

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Starting in 1986, Williams, Billy Crystal, and Whoopi Goldberg co-hosted HBO’s Comic Relief to raise money for the homeless. Soon after Williams’s death, Crystal went on The View and spoke with Goldberg about his friendship with Williams. “We were like two jazz musicians,” Crystal said. “Late at night I get these calls and we’d go for hours. And we never spoke as ourselves. When it was announced I was coming to Broadway, I had 50 phone messages, in one day, from somebody named Gary, who wanted to be my backstage dresser.”

“Gary” turned out to be Williams.

A version of this story ran in 2018; it has been updated for 2021.