It's odd to think that there was a time when the Yankees baseball cap was, well, just a baseball cap, just another part of the New York Yankees uniform. It was functional. It shielded players' eyes from the sun, kept sweat from their brows, and showed which team a player was on. But it wasn't a fashion statement.

Today, however, the Yankees cap is ubiquitous. Everyone—from athletes, actors, and musicians, to your parents, friends, and kids—knows, and quite possibly wears, the iconic baseball hat. The cap reached true icon status recently, as one of the debut items in the Museum of Modern Art's exhibit, "Items: Is Fashion Modern?" which runs through January 28, 2018. Here's how it went from the confines of the baseball diamond to changing the course of fashion.

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Spike Lee changed everything.

New Era, the company that makes hats for Major League Baseball, started working with the MLB in the 1920s, debuted its signature 59Fifty hat in 1954, and became the official on-field hat for every MLB team in 1993. In 1996, Spike Lee requested a personalized Yankees cap—one that wasn’t in the team’s signature navy wool.

"Back in '96, Spike Lee called and asked us to make him the Yankees baseball cap in red," says Chris Koch, CEO of New Era. "That moment started the fashion, street culture side of our business. It changed the way the world looked at headwear."

Before Spike's request, hats had only ever been made in the color of their team. A New Era Yankee’s cap was navy wool with a white Yankees symbol. But the same cap, made in a personalized color, opened a world of opportunity for the brand—and for fashion.

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The Yankees celebrate their 1996 World Series Win against the Atlanta Braves.

The Yankees’ success helped, too.

Of course, Spike's red cap was coming at an opportune time: After more than a decade of middling baseball, the Yankees emerged in the mid-'90s as one of the league's most dominant teams.

"Twenty-seven championships," says Mariano Rivera, arguably one of the best relief pitchers of all time, who logged 19 seasons with the Yankees from 1995 through 2013. "That’s what made the hat so iconic. And the many players that wore that uniform, that wore that iconic hat. They made it happen."

Fans wanted to wear the cap, too. And options of colors and styles made it personal to them. New Era rolled out more new styles soon after Spike's red one: pinks and tonal blacks, stretchy, fitted, and flat-brimmed. The cap flooded every cultural arena. It was not only in stadiums, but also in fashion, music, and the local mall. It became culture.

"It fits part of the sentiment that athletes want to be rock stars, and rock stars want to be athletes," says Koch. "Then you add the fashion side in, and all the lines become blurred—it all goes together. Now, the iconic 'NY' logo is recognized around the world. It’s a mark that stands on its own."

Today the Yankees cap is everywhere.

This is where the MoMA exhibit comes in. "Items: Is Fashion Modern?" is a detailed look at 111 items that shifted culture. Although there are high-fashion moments of influence, the exhibit is focused mostly on the homegrown American classics: the Champion hoodie, the graphic T-shirt, the New Era Yankees cap.

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"The exhibit epitomizes what has been essential to our culture," says Chay Costello, associate director of merchandising at MoMA. "We always look for opportunities to engage with the community around an exhibition. This is a very different type of show; how could we share it with the public?"

Because of its cultural constancy, the New York Yankees cap is one of the most recognizable pieces of the exhibit. Plus, its presence illuminates how deeply the baseball cap is ingrained in everyday fashion; it’s hard to imagine there was a world where it didn't exist.

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