A thumbprint has been found on the buttocks of a wax model of a sculpture by Michelangelo in the collection of the V&A Museum. The dark red wax figure was made around 1516-1519 and is the only autograph model by Michelangelo in the museum.

Senior curator Peta Motture says: “It is an exciting prospect that one of Michelangelo’s prints could have survived in the wax. Such marks would suggest the physical presence of the creative process of an artist. It is where mind and hand somehow come together… he destroyed a lot of [the wax models] himself. A fingerprint would be a direct connection with the artist.”

The model, or bozzetto, is a rough sketch of Young Slave, an unfinished marble sculpture now in the Galleria in Florence. It was meant to be one of the many, many statues Michelangelo planned for the tomb of Pope Julius II but never completed. The first plan for Julius’ tomb, commissioned in 1505, eight years before his death, was a monumental free-standing multi-story mausoleum with more than 40 statues, life-sized and larger, that was supposed to be installed in the Cappella Maggiore of St. Peter’s Basilica. The Young Slave was one of four intended to be used as columns, telamons in prisoner form, for the lower level of the tomb. They were deleted from the plans during one of the many downsizing redesigns and remained in Michelangelo’s studio until his death when they were given to Duke Cosimo I de Medici.

Julius died in 1513 with no tomb in sight. His heirs demanded that Michelangelo come through, albeit in much reduced form with a wall tomb. Even the smaller-scale tomb took another thirty years for Michelangelo to complete. The finished product was a modest arrangement with seven statues including the famous Moses with horns in the minor basilica of St. Peter in Chains.

Over the decades, Michelangelo created many drawings and models for this boondoggle of a papal tomb, and because he was already famous in his lifetime, his contemporaries managed to snag some of those preparatory works before the temperamental master could destroy them (which he did to many of them). The V&A’s Young Slave is one of very few surviving wax models by Michelangelo.

The wax figure is 6.5 inches high (the full-sized marble is more than seven feet tall) and was molded onto a metal armature allowing the artist to alter it easily as he worked on his final vision. Indeed, the sketch model has several points of difference from the marble, particularly in the left leg. Also the shoulders and back were never carved in the marble.

According to art historian Giorgio Vasari, who was a personal friend of Michelangelo’s, the wax was prepared by mixing animal fat, turpentine and black pitch to make it malleable but durable. The red color was produced by adding red earth, vermillion or red lead. Vasari also said that Michelangelo had a unique method for using his wax models to make the sculptures. He put the bozzetto in a box, filled it with water until the model was fully submerged, then removed the water gradually. Whatever parts peeked up above the water first, he carved out of the marble.

NB: We don’t know if this is accurate because Vasari never saw Michelangelo carve anything at all. Michelangelo adamantly refused to allow anyone to observe his process, not even his friends. That’s one of the reasons his prep sketches and models were so coveted by other artists, because it was the only way they would ever get a glimpse into how the Michelangelo magic happened. It’s also why there’s a very good chance that the thumbprint was Michelangelo’s because he was the only one who got to see his unfinished works, let alone touch them.