A mood board methodically arranged with haunting pictures of the last tsar's family and their lost world cued the fairy-tale princess feel of Maria Grazia Chiuri and Pier Paolo Piccioli's new couture collection for Valentino. One dress—dévoré-ed flowers on a sheer background, with pleated tulle wings flying from the shoulders—was so Neverland-ready that it was a wonder it didn't elevate then and there from the catwalk.

A similar magic infused much of the rest of the collection, even daywear like the tweed suit that was gilded with gold and platinum. There was a fearlessness in the fact that so much of it was so old-fashioned, in specifics like the buttons running up the sleeve of a governess-y pale crepe gown or down the back of a black cashmere coat, or, more generally, in the neo-medieval restraint and decorum of long-sleeved, floor-length gowns. One, in black velvet, was practically penitent. But Chiuri and Piccioli's signal achievement has been to turn the old-fashioned into something new and irresistible. "A sense of memory," was Piccioli's cryptic clue. "Not nostalgic," Chiuri added quickly. True, how could they—or any of their glamorous young clientele—possibly be nostalgic about a period they had no direct experience of? But what the designers seemed to be talking about was the way they have managed to take the foundations of haute couture—the incredible, time-consuming, numbingly detailed techniques—and applied them to their own curious vision. Take that penitent black velvet gown, for instance. A few outfits later, it opened up into a delicate Gothic lattice that was suggestively contemporary.

Delicacy as a signpost of technique was also obvious in a cocktail dress spun from a net of crystals, or a petaled skirt with a tracery of platinum. Hair-meister Guido Palau's fragile gold-and-crystal diadems were a sterling accessory. But equally, there were outfits that seduced with their straightforwardness. A Cossack-collared white wool jacket over a long skirt saw the White Russian princess in daywear mode. And a simple panne velvet gown—braided at the neck and waist, slashed open at the back, and rendered in an elusive shade of eau de nil—was quite possibly dress of the week.