Franca Sozzani is the editor in chief at Italian Vogue; she also invented Instagram.

At least, that’s how she sees it. Born and raised in Italy, she was confronted by the limits of her native tongue when she became editor of the iconic magazine in 1988. “How can I talk to everybody in a language no one understands?” she asked herself. “I had to use images.” Pre-social media, Sozzani intuited the human desire to communicate visually. For this reason, she says with a laugh, “I was Instagramming 25 years before everyone else!”

As revealed at Friday’s kickoff event in the 2014 Fashion at Stanford Speaker Series, being on the cutting-edge of fashion requires this special sort of insight. To intimately know the style of an era is to be immersed in that era, a well-dressed anthropologist studying the sentiments and cultural events that manifest themselves, however obliquely, in a white T-shirt and leather jacket.

“Not everything in fashion happens on the runway,” she said. “Some of the best trends start in the street. This is then taken up by the movies.”

Fashion is, of course, how one looks; but it is also implicitly why one looks that way and how it came to be that go-go boots made perfect sense with mini-dresses one fateful day in 1966. Trends don’t spring out of workshops with the suddenness of genius; they are not born but distilled, from discos and offices and universities, as well as from magazines. They have such staying power with the public (think of the ubiquity of skinny jeans) precisely because, as cultural conglomerations, they are returning to the social space from which they came, only this time in a sleeker package.

One of Sozzani’s many jobs is to keep tabs on these social forces and recognize the moments when they meet, creating something exceptional. “Not everything in fashion happens on the runway,” she said. “Some of the best trends start in the street. This is then taken up by the movies.”

Sozzani loves the movies. In her talk, she took us through a rich and varied list of films in which fashion played a major role, movies that catalyzed a trend—think of Audrey Hepburn’s waifish charm—or crystallized a fashion moment that could only happen then and there—Barbarella. This was as much a review of fashion’s high points as a crash-course in cinema history.

In visiting The Wild One (1953), we were reminded of Marlon Brandon’s classic badass get-up, which still resonates in today’s tight jeans and heavy jackets. We looked at Catherine Deneuve, the epitome of Parisian chic in her pleather trench coat and Wednesday Adams-esque mini-dress, in the 1967 Belle du Jour. We touched on the unexpected success of hats: Faye Dunaway’s cheeky beret in Bonnie and Clyde (1967) and the furry pillbox hats of Doctor Zhivago (1965).

We looked at the gender-bending lingerie-inspired vampiness of Cabaret (1972), The Night Porter (1974), and The Rocky Horror Picture (1975), prime examples of film and fashion’s joint power to tap into society’s subterranean desires. Jesus Christ Superstar (1973) and Hair (1979) showcased the eclectic hippie fashions of the ‘60s long before bohemian chic hit the runways in 1973. Anne Keaton’s menswear in Annie Hall (1977) and John Travolta’s white suit in Saturday Night Fever (1977) both made waves in the fashion world.

Reality Bites, featuring Winona Ryder in XL thrift-store dresses and Doc Martens, ushered in what Franca called “the grunge,” which was carried on by the young stars of The Clerks (1994) and American Beauty (1999). She pinpointed Wes Anderson’s 2001 The Royal Tennenbaums as the genesis of hipsterdom, with its pairing of tennis sportswear with quirky vintage (plus unsmiling characters).

“Movies,” she reminded us, “are a mirror.” An iconic film reflects not only the trends du jour but also the attitude, in a far less abstract way than the runway.

Sozzani went on to mention movies that paid specific homage to a time-period via their costumes, like Sofia Coppola’s contemporary reimagining of the French queen in Marie Antoinette (2008), or Kubrick’s visionary 2001: A Space Odyssey (1968) which paid tribute to an as-yet unimaginable future through its tidy white spacesuits. She mentioned explicit collaborations between fashion designers and film directors: Givenchy’s involvement in 1961’s Breakfast at Tiffany’s is probably the first to spring to mind. She discussed the lesser-known role of Armani in the costume design of American Gigolo (1980), which was followed up by Armani’s design of the suits for the 2013 hit The Wolf of Wall Street.

Throughout her talk, Sozzani prompted us to consider: what do these movies and their fashions say about the time period in which they were made? “Movies,” she reminded us, “are a mirror.” An iconic film reflects not only the trends du jour but also the attitude, in a far less abstract way than the runway. Not everyone looks like a model or dresses in couture, she said, but everyone can relate to at least some sliver of life depicted by the movies.

She cited the controversial 1966 film Blow-Up as a perfect picture of Swinging London in all its dissolution and excitement, and 1960’s La Dolce Vita (as well as its 2013 remake The Great Beauty) as brilliantly capturing the bourgeois glamour of jet-set Rome. If these films were made just two years later, she explained, they could never have looked the way they did, with the iconic fashions we remember today. They are artifacts of the moment, a moment now behind us but memorialized by its images. Who can forget Sophia Loren’s va-va-voom, or the image of Uma Thurman smoking a cigarette, glaring out at us from under her jet-black bangs on the poster for Pulp Fiction (1994)?

These are the lasting images that inform and empower fashion, our most wide-ranging form of communication as we bustle down a city street. In the eyes of so many strangers, all that we will be remembered by is the way we wore our hair that day. This tiny gesture (short with bangs like Uma? hidden by a rabbit-fur hat? in two little buns a la Miley Cyrus?) connects us to the society in which we’re steeped.

Fashion underlines the present, offering a history lesson that is, in Sozzani’s words, “less boring than books.” It captures a historicized essence, makes visual the here-and-now, just like the movies do. By watching any of the classic films Sozzani described or imitating their fashions, one can fleetingly inhabit the past—or, at the very least, a fabulous pillbox hat.