A black evening gown worn by Princess Diana to a 1994 charity event — chosen deliberately on the night her husband publicly confessed to infidelity — will soon be auctioned at Sotheby's, where it is first being displayed for public viewing. The dress, designed by Christina Stambolian, has spent thirty years becoming something far larger than fashion: a symbol of a woman's quiet insistence on being seen at a moment when others sought to define her. As it passes from collective memory into private ownership, the auction marks a threshold between history held in common and history held by the hig