A basalt stela discovered at Rosetta, at the western mouth of the Nile, during Napoleon's occupation of Egypt, in 1799. This trilingual inscription on stone, a decree of King Ptolemy V (196 BC), was carved in Greek, Egyptian Demotic, and Egyptian hieroglyphic. It provided Jean-François Champollion with the key to the decipherment of the ancient Egyptian hieroglyphs, thus paving the way to modern Egyptology. The Rosetta Stone is now in the British Museum.