Back in 1955, Paramount Studios’ legendary costume designer Edith Head sized up a young actress named Grace Kelly and handed her a sac à dépêches, a simple leather handbag made by Hermès in Paris. Because she worked for Alfred Hitchcock, Head could pretty much buy what she wanted. And to Head’s unerring eye, the 26-year-old Kelly, starring alongside Cary Grant in To Catch a Thief, required a simple, stylish purse. The bag’s appearance in the film was forgettable, but a year later—and shortly after Kelly married Prince Rainier of Monaco—she used the bag to deftly conceal her obvious pregnancy from the paparazzi. While the photographers popped their flashbulbs, eyes popped over the beautiful leather accessory, and Hermès’ sac à dépêches became, simply, the Kelly Bag.