For royal watchers, Princess Margaret is an eternal “It girl” of the British royal family. As The New York Times once put it, the princess “spent most of her life playing the role of the royal family’s most celebrated black sheep.” Margaret was known for her beauty, style, and glamour—and her love of a good party. Margaret would go on to marry the photographer Antony Armstrong-Jones, whom she met at a dinner party in 1958. Below, we share 27 iconic photographs of Princess Margaret, from her World-War II era childhood, to her London wedding at which she wore the Poltimore Tiara, to her night out with The Beatles, to her adult years hanging with Mick Jagger.