A long-lost painting by a master artist of the Renaissance was recently rediscovered in the storeroom of an Italian museum near Milan, according to The Art Newspaper and The Wall Street Journal.

The painting in question, Andrea Mantegna’s 15th century The Resurrection of Christ, was found by a curator at an art museum in the city of Bergamo. The Accademia Carrara has been in possession of the Mantegna painting since the 19th century, but long ago discounted it as a copy. While working on a catalogue for the museum in March, Accademia Carrara curator Giovanni Valagussa took note of the tempera-on-panel work and began to investigate its origins.

Count Guglielmo Lochis purchased the painting in 1846, cataloguing it as an original Mantegna; it was bequeathed to the museum as part of his collection after his death in 1859. But decades later, other experts cast doubt on the originality of the work, first re-attributing it to the artist’s son, and later suggesting that it was a copy that was not even made in his workshop. The museum removed it from display sometime before 1912, and it has been in storage for more than a century.

The Resurrection of ChristAndrea Mantegna, Accademia Carrara

Upon inspecting the painting, Valagussa suspected it was more than just a copy. The painting features a small cross at the bottom of the image that looked disconnected from the rest, and the structure of the back of the painting made it seem like it might be part of a larger work. Valagussa tracked down another Mantegna painting, Descent Into Limbo, that seemed to fit underneath—the paintings are likely two halves of one image that was cut apart.

The Accademia Carrara also conducted an infrared survey of The Resurrection of Christ, discovering that the artist drew nude figures first, then painted over them with images of clothed soldiers, a technique that Mantegna was known for.

A world expert on Mantegna, the Metropolitan Museum of Art’s Keith Christiansen, did his own analysis and believes the painting in Bergamo to be an authentic, high-quality Mantegna. That means that the Accademia Carrara’s forgotten wood panel, previously insured for around $35,000, is probably worth between $25 million and $30 million.

The museum hopes to one day bring the two parts of the painting, The Resurrection of Christ and the privately owned Descent Into Limbo, together in an exhibition in the future.

[h/t The Art Newspaper]