A painting which resurfaced 24 years after its theft from the Galleria d’Arte Moderna Ricci Oddi in Piacenza is an authentic work by Austrian artist Gustav Klimt, experts have confirmed.

‘Portrait of a Lady’ (1917) was finished by Klimt one year before he died. It was purchased by Italian art collector, Giuseppe Ricci Oddi, in 1925 and hung in the billiard’s room of his palazzo. The Ricci Oddi Museum first realised the portrait of an elegant young woman was missing on the morning of 22 February 1997. Police believed it had actually been removed three days earlier and investigators suspected an inside job.

The discovery of its frame on the roof of the Ricci Oddi Museum led some to believe the perpetrator used a fishing line to hook the work off the wall and pull it through an open skylight. That theory was dismissed in 2016 when one of the original investigators on the case told reporters the skylight wasn’t big enough. The theft became one of the greatest mysteries of the art world and the painting, one of the world’s most sought-after stolen artworks.

The portrait was finally found hidden in the wall of the Ricci Oddi Museum by gardeners on 10 December 2019. While clearing ivy from the walls, they discovered a metal pane, which opened to reveal an alcove. Hidden inside the alcove was a bag containing the missing painting. Conservation experts have confirmed the painting is in good condition except for a scratch that is thought to have occurred when the work was removed from its frame.

The verification of the work was announced by Piacenza prosecutor, Ornella Chicca, on Friday, 17 January 2020. “It’s with no small emotion that I can tell you the work is authentic”, she told reporters at a press conference as she stood beside the painting. Piacenza councillor, Jonathan Papamarenghi, said it was “a great, great moment for the city, and for the art community”.

With the joy of the discovery come several questions as to how the painting came to be hidden in the wall of the Museum. The identity of the perpetrator and whether or not the painting even left the grounds of the Museum remain shrouded in mystery. At Friday’s press conference, Chicca said authorities were now studying traces of organic material found on the canvas for clues.

The verification of the work was carried out by a team of experts from Bologna. Key to authenticating the work were stamps found on the back of the canvas indicating the portrait’s exhibition history and X-ray analysis revealing the existence of an earlier painting. Experts had been expecting to see this earlier work, which also featured a portrait of an elegant young woman, as a result of research findings made by an art student one year before the work’s disappearance.

The art student studied the similarities between 1917 portrait and another Klimt work from 1912, previously thought lost. Both works depicted a young woman although the earlier work showed her wearing a scarf and hat. The student’s investigation led to the realisation that the 1917 work had been painted over the earlier work. This made it the only known double portrait executed by Klimt and proved indispensable to verifying the authenticity of the Ricci Oddi portrait.

Film companies and book publishers have already begun contacting the Ricci Oddi Museum with a view to adapting the painting’s remarkable story. In the meantime, the Museum is planning an international conference in celebration of the discovery and hopes to exhibit the painting alongside two other works by Klimt held by museums in Rome and Venice in a display of “Italian pride”.