Princess Diana was never one to play by the rules. She wore her heart on her sleeve, omitted “obey” from her wedding vows, embraced AIDs patients, and, in an unforgettable fashion moment, broke from a long tradition that discouraged the royal family from wearing black unless in mourning. Enter the “revenge dress”—jet-black, off-the-shoulder, designed by Christina Stambolian, and worn by Diana to a Vanity Fair party at London’s Serpentine Gallery on June 29, 1994, the very same day her husband Prince Charles admitted to infidelity on national television. The princess had planned to wear a different gown, but switched to the little black dress as a declaration of self-possession and agency, sending shock waves around the world. “She could not have got her message across more clearly had she shouted it to the sky: ‘I am not a victim anymore!’” wrote the journalist Georgina Howell. “The performance worked brilliantly. The public adored it: Diana was back.” That dress now goes up for auction at Sotheby’s Luxury Week. After a first showing in London, and before its sale in New York, the dress will travel to Hong Kong and Geneva. Part of the proceeds from the sale will be donated to NHS Lothian Charity on behalf of the Royal Edinburgh Hospital. —Maggie Turner