Luigi Lo Rosso discovered the painting in a home in Capri in 1962 and took the rolled up painting home with him to Pompeii, hanging the painting in his home for the next few decades. 

The portrait is now believed to be a distorted image of Dora Maar, a French photographer and painter who was Picasso’s mistress. The artwork featured Picasso’s signature in the top left-hand corner. But Lo Rosso didn’t know who he was. After questions by his son Andrea years later, the family started to wonder if the painting was of significance, the Guardian reports. 

The family eventually sought the advice of a team of experts and after years of investigations, Cinzia Altieri, a graphologist and member of the scientific committee of the Arcadia Foundation, which deals with the valuations, restorations and attributions of art works, confirmed that the signature on the painting was Picasso’s.

The painting is currently valued at €6m (£5m).