In 1973, an American art student in Florence, Italy, stumbled upon a Lost Leonardo da Vinci sculpture in the Museo Archeologico. The unattributed bronze horse (inv. #446) was being used as a mere prop to support an ancient Etruscan riding boy. The art student knew the small bronze horse was by Leonardo because Leonardo made a famous drawing of it, now in the Windsor Royal Library (#358.) There are numerous visual links between the sculpture and the drawing. The most compelling evidence is a small, unique saddle fold that is clearly visible on the sculpture and the drawing. If Leonardo drew the small bronze horse, it is highly likely that he sculpted it. It seems contrary to Leonardo's character to draw a horse he didn't make. The art student naively assumed (given the strong visual link to a known Leonardo drawing) that it would be relatively easy to attribute the small bronze horse to Leonardo da Vinci. But this attribution hypothesis has failed to gain any support from the professional art historians who seem to control the attribution process. Over four decades later, the same art student, Mark Fondersmith, now an art director and sculptor, is still trying to scientifically prove this hypothesis by x-ray fluorescence (XRF) analysis and restore a Lost Leonardo to the people of Florence, Italy, and the world.