When Pierre-François Bouchard’s men discovered the ancient stone slab that would change the world on July 19, 1799, they weren’t on an archaeological dig; they were doing a last-minute construction job. The French soldiers occupied a run-down fort in Rosetta, Egypt, and had just days to shore up their defenses for a battle with Ottoman Empire troops.

As the men tore down a wall that had been built using the detritus of nearby ancient Egyptian sites, they discovered a large stone fragment covered in three types of writing, including ancient Greek. Intrigued, Bouchard wondered if the stone might say the same thing in three different languages. He shared his find with French scholars who had come to plumb Egypt