During the summer of 2018, while construction workers were restoring a former office that was to be the new Oscar de la Renta boutique in Paris, they came across an extraordinary treasure.

The construction workers discovered the work by noticing the existence of a 19th-century paneled ceiling, consisting of 29 square panels inlaid and painted with heraldic seals, kept for decades under a second ceiling. It was by felling the wall a little later that the team discovered a massive painting, 20 x 10 feet, blackened by time, that extended over the entire surface of the wall. The painting depicts horseback riders wearing 17th-century clothing as they stop in front of the city of Jerusalem, with a mosque in the distance.

Image ©Julien Mignot for The New York Times Image ©Julien Mignot for The New York Times

Although Alex Bolen, the chief executive of Oscar de la Renta, has known about the work for a year, he decided to keep the information secret until Paris Fashion Week in January 2019. He consulted Stéphane Pinta, an expert in Old Master's paintings at the art firm Turquin, who established that it was an oil on canvas from 1674, painted by Arnould de Vuez, a Flemish artist who worked for the court of King Louis XIV alongside Charles Le Brun, the foremost court painter. Pinta traced the provenance of the masterpiece through a journal by Albert Vandal that articulated the travels of Charles-Marie-Francois Olier, Marquis of Nointel and Angervilliers, who was Louis XIV's ambassador in Palestine. A print similar to the large painting appears on page 129 of the book: it represents the Marquis de Nointel arriving in Jerusalem accompanied by his cavalry, during a tour of the Middle East carried out in 1673.

Rendering of the Oscar de la Renta boutique on Rue de Marignan. Photo: Bangkok Post Rendering of the Oscar de la Renta boutique on Rue de Marignan. Photo: Bangkok Post

The Oscar de la Renta boutique was originally planned to open in time for Paris Fashion Week, but the renovations had to be interrupted to restore the masterpiece, which will likely delay the opening until at least May.

Experts believe the masterpiece was glued to the wall in order to hide it from the Nazis who confiscated valuable art during the 1930s in major cities like Paris, Vienna and Berlin. Due to its precarious attachment to the wall, experts have declared that it would be too dangerous to try to move it. Bolen has negotiated with the owner of the building so that the painting will remain in the shop once it is open (the lease is scheduled for 10 years), in return for fully funding the restoration.

The restorer TK at work, image ©Julien Mignot pour The New York Times The restorer TK at work, image ©Julien Mignot pour The New York Times

The specialist Benoît Janson, as well as his team, have been working for several months to restore the painting, which he considers "rare and exceptional in many ways". According to Janson, the painting is covered with several layers of varnish due to previous restorations, which tarnished the colors of the canvas. The extensive work of the specialists should be finished by May, in time for the opening of the store, an atelier of both sartorial and artistic treasures.

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