Spain’s much admired and beloved queen was utterly charming and engaging and the essence of regal graciousness, gamely posing for the jostling hordes of photographers. Designers including Diane von Furstenberg, Narcisco Rodriguez, Ralph Rucci, and Tomas Maier admired the extraordinary clothes, noticing details of cut and construction that only a designer’s eye might catch.

Some guests wore Cristóbal. The immensely chic Mrs. Derald H. Ruttenberg, who has lent three pieces of her own to the exhibition (including a whimsical pale mink suit) wore the designer’s silver lamé double-face coat. Jill Spalding wore her mother’s knife-pleated black taffeta skirt and cape from 1949. Regina Drucker wore an early-sixties evening coat of rosy taffeta. Others channeled Balenciaga: Carolina Herrera wore her own papal-purple satin; Milly de Cabrol wore Barbara Tfank’s crimson Balenciaga homage. Alba Clementeand Lee Radziwill were chic as ever in cardinal red. Meanwhile Deeda Blair came as an ambulant Goya in clouds of black gauze, and Daphne Guinness wore a mantilla comb. 

A very intimate post-exhibition dinner for Her Majesty was given by the Julio Santo Domingos in their exquisite, treasure-trove apartment. Lauren Santo Domingo was dressed in a froth of Chanel black tulle and rhinestones, Beatrice Santo Domingo was stunning in whorl-shaped JAR earrings in alternate arcs of rubies and diamonds. 

“I love stacked Míros,” said Diane von Furstenberg of the salon-style hanging of breathtaking artworks. And yes, that enchanting little equestrian portrait is by Goya.

The following day a pan-generational group of fashionistas descended on the institute for a matinal preview. Designers Jason Wu and Pamela Love and Georgina Chapman andKeren Craig, joined Amanda Brooks and Shala Monroque, Olya Thompson’s adorable daughter Natalia came dressed as a matador complete with bright-pink medias (stockings) and a chaquetilla (short jacket) by Stella McCartney. Natalia liked the 1954 red velvet dress with pearls and her friend Poppy Halard liked the 1957 bride’s dress best, and they both agreed that the 1960 black gazar dress with the roses was the nicest choice for their flamenco lessons. They sat transfixed by the Tom Kublin film footage of Balenciaga’s fashion shows from 1960 to his final collection in 1968; the evening before, Deeda Blair andRalph Rucci had done the same.

At the Queen Sofía Gold Medal Gala on Thursday night, flamenco ruffles were the order of the day. Queen Sofía was superbly dressed by Oscar de la Renta in Míro blue and turquoise satin, and jet-haired Sonsoles Díez de Rivera wore her mother’s 1947 powder-blue velvet-and-jet matador jacket—a match to the ruby version from the Costume Institute included in the exhibition – and gave one a vivid sense of the immense style of Balenciaga’s clients.