There are fewer than 20 surviving paintings by Leonardo da Vinci, and also many fake paintings that people claim are his “lost” work. This year, an Italian art historian says that a profile of the Archangel Gabriel painted on a glazed tile is a self-portrait by Leonardo at age 18.

If true, this would make it the oldest known painting by the original Renaissance Man. But according to art experts, it’s probably not authentic.

The assertion comes from Ernesto Solari, a Leonardo scholar, and Ivana Rosa Bonfantino, a handwriting expert. They stake their claim on a tiny jawline signature on the work, reading “Da Vinci Lionardo,” dated 1471. Bonfantino analyzed the signature and claimed it was a close match to those on Da Vinci’s established works.

The last credible Leonardo to be identified was Salvator Mundi, or “Savior of the World.” Robert Simon Fine Art announced its discovery in 2011, and the painting of Christ sold for a record $450 million in 2017. Before that, the last credible Leonardo discovery was Benois Madonna in 1909.

“They don’t come around very often,” says Robert Simon, president of the gallery that led the reevaluation of Salvator Mundi. In Simon’s opinion, the newly-surfaced angel profile isn’t legit.

“Of the many paintings that are proposed to be by Leonardo, this seems to be about the least likely,” he says. “I think it’s absolutely preposterous, and it has no resemblance to any Leonardo. Nor does it appear to be a painting of the period.”

Martin Kemp, one of the art experts who evaluated Salvator Mundi and determined it was credible, doesn’t think the angel portrait is a lost Leonardo either.

“The chance of its being by Leonardo is less than zero,” the Oxford emeritus professor of art history told The Guardian. “The silly season for Leonardo never closes.”

Previously, Kemp told National Geographic that he’s “assailed with new Leonardos every day of the week, virtually.” Some of them receive media coverage, like La Bella Principessa, a profile portrait supposedly depicting an Italian noblewoman. In 2015, the British art forger Shaun Greenhalgh revealed the painting was his, and the person in it was a check-out woman.

“I think they’re pretty constant,” Simon says of these fake claims. “[Leonardo] seems to be a subject for a lot of speculation, and fantasy as well, over the years. I certainly get sent a lot of putative Leonardos.”