Leonardo da vinci died at the age of 67 on May 2, 1519, at the small manor house in the Loire Valley given to him by King Francis I of France. He was buried nearby in the church of the Château d’Amboise, which was demolished in the early 19th century. An excavation decades later turned up bones that were believed to be Leonardo’s.

An inscription notes carefully that the site holds the artist’s “presumed remains.” The acknowledgment of uncertainty is a mark of quiet candor, and unusual in this case: Leonardo enthusiasts are not famous for their restraint. Give them a small mystery and a bit of wiggle room, and the theories come quickly.