The Salvator Mundi dispute isn’t the first time the provenance of one of Leonardo da Vinci’s precious few surviving artworks was challenged. In the 1950s, the French merchant Raymond Hekking bought an early-17th-century replica of the Mona Lisa from an antiques dealer in a village outside Nice, and then embarked on a media-fueled crusade to convince the world he had the real thing. His theory? That the Mona Lisa in the Louvre was the replica—a fake returned after the infamous 1911 theft by Vincenzo Perugia—and that Hekking had stumbled on the original. The theory didn’t take, but Hekking’s insistence was admirable. The replica is expected to sell for $250,000 to $350,000 when it goes on sale at Christie’s. —J.V.