As art history lovers flock to the Louvre in Paris to see the blockbuster show celebrating the 500th anniversary of the death of Leonardo da Vinci, a new painting by his hand may have been discovered at a French chateau.

The work, a portrait of a bald man that has been in the historic house for centuries, could be by the Renaissance master, although the evidence is far from clear.

A 145-year-old letter mentioning a portrait of the philosopher Niccolò Machiavelli by Leonardo was discovered last year in the archives of Château de Valençay in central France. The chateau once belonged to Charles Maurice de Talleyrand-Périgord, the French diplomat known better as Talleyrand, who died in 1838 after serving under several French regimes, including Napoleon’s.

The director of the historic house, Sylvie Giroux, told Agence France Presse that “it is not impossible” that Leonardo painted the Italian political theorist, best known for his political treatise, The Prince.

The Château de Valençay. Photo by Jean-Christophe Benoist, via Wikimedia Commons.

The local archivist, Anne Gerardot, is more cautious. “Just because it says so in the archives does not mean it’s true,” she told AFP, noting that she thinks the Old Master portrait more closely resembles the French Renaissance essayist Montaigne.

There’s also the issue of the painting’s wooden support, which has a smooth appearance uncharacteristic of Leonardo’s time. It could be the result of restoration work done in the 1890s, or a clue that the painting was made at a later date.

Is this a portrait of Niccolò Machiavelli—and is it by Leonardo? Photo courtesy of the Chateau de Valencay.

But the painting, featuring a thin, bearded figure in a black coat and white shirt with necktie, does match the description in the letter, which mentions a portrait on wood measuring 22 by 17 inches. In the letter, which is dated 1874, the estate manager who wrote it says: “I am having the concierge wrap up and put on the train a box containing a painting (Machiavelli by Leonardo da Vinci).”

The chateau plans to submit the painting to a battery of tests in the hopes of determining its subject and authorship. If it is indeed by Leonardo of Machiavelli, it could be the first proof that the two men had met.