Italian art experts believe they’ve found the earliest work created by Leonardo da Vinci, CNN reports. The image of the Archangel Gabriel, painted onto a square tile, is dated 1471 and signed “Da Vinci Lionardo.”

If authentic, the work—still in pristine condition—would have been painted by Leonardo when he was just 18 years old. Ernesto Solari, an expert on the artist’s works, and Ivana Rosa Bonfantino, a handwriting expert, spent three years investigating the origin of this piece.

Descendants of the aristocratic Fenice family of Ravello, Italy, reportedly found the painted tile while they were cleaning out their house. Bonfantino said the signature on the tile is a “very close” match with other samples of the artist’s handwriting.

The depiction of Archangel Gabriel is believed to have been painted in Leonardo’s own image, The Guardian reports. The tile contains a coded message of numbers and secret inscriptions that Bonfantino translated as “I, Leonardo da Vinci, born in 1452, represented myself as the Archangel Gabriel in 1471.”

Not everyone is convinced, though. Another Leonardo expert, Martin Kemp, dismissed this claim and told The Guardian, “The chance of its being by Leonardo is less than zero.” Like many works purportedly by Leonardo—including the most expensive painting in the world, Salvator Mundi—the tile painting is sure to be the subject of academic debate for some time to come.

[h/t CNN]