Rosetta Stone, a slab of black basalt that provided scholars with their first key to ancient Egyptian hieroglyphic writing. Using the Rosetta Stone as a dictionary, scholars were able to translate other inscriptions and manuscripts written in hieroglyphics. The stone was discovered in 1799 near Rosetta, Egypt, by a French engineer of Napoleon's army. Three years later it was acquired by the British Museum. It is about three and one-half feet (1 m) long, two and one-half feet (76 cm) wide, and one foot (30 cm) thick. On it are inscriptions in three kinds of writing—hieroglyphic, demotic (simplified hieroglyphic), and Greek.

The Greek text was read easily. It is a decree prepared in 196 B.C. by a group of priests ordering the commemoration of the first anniversary of the coronation of their pharaoh, Ptolemy V Epiphanes. The priests praised the pharaoh for many laudable deeds, such as canceling overdue taxes and granting amnesty to prisoners. In closing, the decree directed that it be inscribed in hieroglyphic, demotic, and Greek on stone slabs.

The hieroglyphs proved most difficult to read, because of the false assumption that hieroglyphs were only symbols for words and did not represent sounds. An English scholar, Thomas Young, made some important progress in identifying some of the proper names, such as Ptolemy, in the demotic and hieroglyphic texts in 1819. In 1822 a French scholar, Jean-Francois Champollion, drawing upon his knowledge of the ancient Coptic language of Egypt, correctly determined that the hieroglyphs represented both sounds and words, thus finding the key to the translation of hieroglyphics.