I admit it.

I was a very geeky Star Wars fan. On May 25, 1977, 40 years ago today, I cut school with a couple of other junior high school buddies to see the highly anticipated opening of George Lucas‘ magnus opus at the Astor Plaza Theater in Manhattan.

I own original Star Wars posters, buttons, trading cards and various promotional items from that period. I even created a quiz that tested the Star Wars acumen of my friends, to very nerdy depths.

One thing I didn’t know at the time was that the iconic baddie in black, Darth Vader, was represented by more than two people. We all knew that David Prowse was the body inside, and that James Earl Jones intoned Vader’s menace with his breathy baritone. But we didn’t know that the swordbuckling Vader was animated by a 1952 Helsinki Olympian from England named Bob Anderson.

Anderson of Alverstoke, Hampshire served in World War II with the Royal Marines, where, according to The Independent, he learned how to fence. After the war, Anderson found success in competition, succeeding in the 1950 British Empire Games before joining TeamGB at the World Championships and the Helsinki Games. While his team finished fifth, Anderson went on to coach Great Britain’s fencing teams for the next five Olympics. His teams took silver at both the 1960 Rome Olympics and 1964 Tokyo Olympics.

Along the way, Anderson became the go-to guy for swordbuckling fill-ins and fencing choreography in film. He worked with Errol Flynn in The Master of Ballantrae, Johnny Depp and Orlando Bloom in Pirates of the Caribbean, and Antonio Banderas, Anthony Hopkins and Catherine Zeta-Jones in the Zorro films.

He was also brought in to choreograph the lightsaber fight between Obi-wan Kenobi and Darth Vader in Star Wars. When Lucas began work for the sequel, The Empire Strikes Back, it was likely determined that Prowse could not execute the lightsaber duels to the precision desired. That’s when Anderson the choreographer became Anderson the dark lord. It is Anderson who duels with Mark Hamill in The Empire Strikes Back, and it is Anderson’s Vader who cuts Luke Skywalker’s right hand off.

Anderson went on to reprise Vader’s lightsaber scenes in The Return of the Jedi. At the time, however, Anderson’s screen presence was never officially acknowledged. Upon the release of The Return of the Jedi, which I also saw on opening day, May 25, 1983, Hamill felt he needed to let the world know the truth about his on-screen dad in an interview with Starlog Magazine. “Bob Anderson was the man who actually did Vader’s fighting. It was always supposed to be a secret, but I finally told (director) George (Lucas) I didn’t think it was fair any more. Bob worked so bloody hard that he deserves some recognition. It’s ridiculous to preserve the myth that it’s all done by one man.”

I didn’t know this until recently. I will have to add this to my quiz.