The Vitruvian Man is a world-famous drawing that depicts a male figure in two superimposed positions with his arms and legs apart and simultaneously inscribed in a circle and a square. The drawing is attributed as a creation of Leonardo da Vinci. However, a researcher named Claudio Sgarbi, has found some evidence to debate the drawing’s origin. Sgarbi checked out Ten Books on Architecture, and found a figure that’s remarkably similar to da Vinci’s The Vitruvian Man. In a volume of academic papers to be published this winter by the Italian publisher Marsilio, he proposes that the author of the drawing was a young architect named Giacomo Andrea da Ferrara:

What little is known about Giacomo Andrea derives primarily from a remark made in On Divine Proportion (1498), by Luca Pacioli, who described him as both a dear friend of Leonardo’s and an expert on Vitruvius. Leonardo himself records in his notes having had dinner with Giacomo Andrea in 1490, the year Leonardo is thought to have drawn Vitruvian Man. And elsewhere Leonardo mentions “Giacomo Andrea’s Vitruvius”—a direct reference, Sgarbi believes, to the Ferrara manuscript.

Sgarbi’s hunch is that Leonardo and Giacomo Andrea collaborated on their drawings, but few traces of Giacomo Andrea survive, and unearthing more, enough to make Sgarbi’s case definitively, may take years. Still, scholars already find it intriguing. The French historian Pierre Gros, one of the world’s foremost authorities on Vitruvius, says he considers the idea “seductive and convincing.”

One of the few other known references to Giacomo Andrea concerns his death. In 1499 the French occupied Milan, where he and Leonardo had lived since the 1480s. Already admired internationally, Leonardo established cordial relations with the French and safely fled the city. But Giacomo Andrea wasn’t so lucky. He apparently stayed on as a kind of resistance fighter, and the French captured, hanged and quartered him the following year. “Because of his loyalty to the Duke of Milan,” Sgarbi says, “Giacomo Andrea was erased from history”—as was his Vitruvian Man.

Read more in Toby Lester’s piece “The Other Vitruvian Man” in Smithsonian Magazine.