A talented young artist crafts an antique-style sculpture so convincing that his friends suggest selling it as genuine; a wealthy man buys it, later learns it is a fake and returns it for a refund. Most of the time, such transactions are unremarkable, but add names and everything changes—especially if the faker is Michelangelo Buonarroti.

Both Ascanio Condivi’s “The Life of Michelangelo” and Giorgio Vasari’s “Lives of the Artists” recount the story of Michelangelo chiseling a life-size marble figure of a dozing Cupid in Florence in 1495. In Vasari’s version, Lorenzo di Pierfrancesco de’ Medici tells the artist, “If you were to bury it and treat it to make it seem old and then send it to Rome, I’m sure that it would pass as an antique and you could get far more for it than you would here.” After Michelangelo performs unspecified tweaks to the piece, art dealer Baldassare del Milanese sells it to Raffaele Riario, the Cardinal of San Giorgio. Riario later hears a rumor that his Cupid is bogus, confirms it and returns the sculpture to Milanese, asking for his money back.

Apparently, Riario saw only a matter of false advertising, but Vasari held a different opinion. “Cardinal San Giorgio cannot escape censure for what happened, since he failed to recognize the obviously perfect quality of Michelangelo’s work,” he wrote, adding, “There is no gre-ater vanity than to value things for what they are called rather than for what they are.” The Cardinal soon redeemed himself by inviting Michelangelo to Rome, where he made many valuable connections.

The Cupid passed through the hands of Cesare Borgia, Guidobaldo da Montefeltre (the Duke of Urbino) and Isabella d’Este before entering the collections of King Charles I of England in 1634. Scholars believe that it was among the many Royal Collection artworks destroyed in a 1698 blaze at Whitehall Palace. Since then, the Cupid has become an art-historical counterpart to Bigfoot, in the sense that sightings evaporate under close examination. British connoisseur John Pope-Hennessy made an intriguing contribution to this game in 1956, when he debunked a Cupid that had emerged in Italy a century earlier and found its way to the Victoria & Albert Museum. The sculpture is an odd candidate, considering that it lacks wings and is not sleeping. Pope-Hennessy said that 19th-century experts explained these troublesome details away by agreeing that “Michelangelo’s conception of Cupid . . . would certainly have been original.”

Pope-Hennessy claimed that the sculpture in the V&A, which probably depicts Narcissus, is the work of two artists: The torso is a Roman copy of a Greek statue, and the head, which is attached by what he calls “a narrow collar of makeup reaching a depth of a quarter of an inch in front,” was fashioned by a Renaissance artist, possibly Valerio Cioli. This revelation might not end the search for the lost sculpture, but it is fitting to encounter a purported “Sleeping Cupid”—a false version of a fake—that is mostly antique, partly Renaissance and not at all by Michelangelo.