Jean-François Champollion officially informs the Académie des Inscriptions et Belles Lettres in France that he has deciphered the Rosetta Stone.

Jean-François Champollion, also known as Champollion le jeune, was a French philologist and orientalist, known primarily as the decipherer of Egyptian hieroglyphs and a founding figure in the field of Egyptology. Partially raised by his brother, the scholar Jacques Joseph Champollion-Figeac, Champollion was a child prodigy in philology, giving his first public paper on the decipherment of Demotic in his late teens. As a young man he was renowned in scientific circles, and read Coptic, Ancient Greek, Latin, Hebrew and Arabic.

The Rosetta Stone is a stele of granodiorite inscribed with three versions of a decree issued in 196 BC during the Ptolemaic dynasty of Egypt, on behalf of King Ptolemy V Epiphanes. The top and middle texts are in Ancient Egyptian using hieroglyphic and Demotic scripts, respectively, while the bottom is in Ancient Greek. The decree has only minor differences across the three versions, making the Rosetta Stone key to deciphering the Egyptian scripts.

September 27 is the 270th day of the year in the Gregorian calendar; 95 days remain until the end of the year.