Diamonds, corsets, ribbons, and pleats are the style signature of the French monarchy, whether it be ball, ballet, masquerade, or opera. Consider the Yew Tree Ball, which celebrated the marriage of Louis XV’s son, the Dauphin. Eight men dressed as topiary yew trees—one of them the king himself—circulated among the throng in Versailles’ gilded hall of mirrors. As for the stage, Louis XIV had performed in ballets as a youth, using his elevated roles—The Sun King was one of them—as a kind of political public relations. Extraordinary attire was to be seen both on the stage and in the audience. Glittering beauty, imaginative costume, this was cultural capital. At the Louvre, 100 of the 1,644 costume designs in the Edmond de Rothschild collection, which holds works dating back to the reign of François I, are on magnificent display. —E.C.