In March 1958, Vogue reported that “a mold of fashion was broken” when Yves Saint Laurent, all of twenty-one and freshly installed at the house of Dior, presented his first haute couture collection. The ovation was so thunderous it bordered on cinematic. France had a new hero; fashion had a new language. Saint Laurent—sensitive, wildly precocious—had arrived.

Born in Oran, Algeria, and educated at the École de la Chambre Syndicale de la Couture in Paris, Saint Laurent was sketching gowns by the time most children were still figuring out scissors. He would go on to define an era—several, in fact—through a stream of provocations that changed how women dressed and how they felt doing so: le smoking, the safari jacket, the sheer blouse, the pea coat, the Mondrian dress, and, crucially, the concept of Rive Gauche ready-to-wear, which liberated designer fashion from the confines of couture salons.

But for all his innovation, Saint Laurent didn’t quite buy into the cult of the handbag. He never built collections around bags, never fussed over them the way he did with his jewelry or silhouettes. “The importance Saint Laurent attached to jewellery in his work, and the relative lack of prominence he gave to handbags as accessories,” writes Patrick Mauriès in Yves Saint Laurent Accessories, “arguably highlights yet another difference between a couturier and a ‘designer.’” While today’s fashion houses build empires on arm candy, Saint Laurent focused instead on attitude.

That’s not to say there weren’t handbags. There were—some of them marvelous. In the 1960s and early ’70s, they were made by a handful of leather goods suppliers to Saint Laurent’s specifications. The materials were sumptuous and sometimes surprising: Moroccan leather, snakeskin, lizard, crocodile, straw, even tortoise shell. It was under the imaginative direction of Madame Leroux and Madame Perrin that the accessories line came to life, producing bags that winked at function while indulging in form: evening tambourines in velvet, book-shaped purses, music-satchel riffs in foal printed to resemble panther skin. One might feature a horn handle; another, leftover jewelry chains reimagined as a shoulder strap.

By 1969, Jane Birkin—yes, that Jane—was modeling a navy calf shoulder bag from the Rive Gauche collection. Decades before lending her name to an Hermès icon, she was slinging Saint Laurent. The bags may not have received the PR blitz of today’s luxury launches, but they did something far rarer: they reflected an unselfconscious cool, the very Left Bank ease that YSL cultivated so precisely.