Three decades after Indiana Jones uncovered the lost Ark of the Covenant, Deborah Nadoolman Landis began her own archaeological expedition.

Tasked with curating a Hollywood costume exhibition for London’s Victoria and Albert Museum in 2012, the Raiders of the Lost Ark costume designer knew she needed to include her iconic creation: Indy’s signature fedora and brown leather jacket. So Landis, who’s also designed other classics from Three Amigos!, The Blues Brothers, and Michael Jackson’s “Thriller” video, visited Skywalker Ranch, where the movie’s producer, George Lucas, allowed her full access to his archives. When she asked an assistant to guide her toward Indiana’s wardrobe, she was met with a shrug. Instead of labeled racks detailing each piece of clothing, which film it was worn in, and who it was worn by, countless hats and jackets—donned by everyone from stand-ins to stunt men—hung in a room, crammed together without any classification. “She just pointed me in that direction and said, ‘Have a wonderful time,’” Landis recalls.

As the only true authenticator of Indiana Jones’s first khaki attire, Landis stretched her memory 30 years and began sorting through fedoras, hoping one might resemble the original Raiders hat. Each had been stamped with a gold “IJ,” making them impossible to differentiate. But eventually, one hat in particular caught her eye. Unlike the others she’d inspected, this fedora’s interior lining had the original label of Herbert Johnson, the British hatmaker that had supplied the Raiders inventory. Surrounded by Indy paraphernalia, Landis let out a sigh of relief. “I couldn’t imagine that I would find anything from the first film,” Landis admits. “That was Harrison’s no. 1 hat, that was the holy grail. … It was a tingling, hair-on-the-back-of-the-head moment.” After a couple more hours of searching, she found two original jackets with brass zippers and D rings at the hip, which differed from the supply’s other European styles, to complete her dig. The trip, and specifically the hat’s uncovery, “really was cathartic,” she says.

[Read Jake Kring-Schreifels’s piece on the legacy and history of Indiana Jones’s fedora.]