Jean-François Champollion announces that he has deciphered the Rosetta Stone.

The Rosetta Stone is a stele composed of granodiorite inscribed with three versions of a decree issued in Memphis, Egypt, in 196 BC during the Ptolemaic dynasty 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 between the three versions, making the Rosetta Stone key to deciphering the Egyptian scripts.

The stone was carved during the Hellenistic period and is believed to have originally been displayed within a temple, possibly at Sais. It was probably moved in late antiquity or during the Mamluk period, and was eventually used as building material in the construction of Fort Julien near the town of Rashid (Rosetta) in the Nile Delta. It was discovered there in July 1799 by French officer Pierre-Franois Bouchard during the Napoleonic campaign in Egypt. It was the first Ancient Egyptian bilingual text recovered in modern times, and it aroused widespread public interest with its potential to decipher this previously untranslated hieroglyphic script. Lithographic copies and plaster casts soon began circulating among European museums and scholars. When the British defeated the French they took the stone to London under the Capitulation of Alexandria in 1801. Since 1802, it has been on public display at the British Museum almost continuously and is its most visited object.

Study of the decree was already underway when the first complete translation of the Greek text was published in 1803. Jean-Franois Champollion announced the transliteration of the Egyptian scripts in Paris in 1822; it took longer still before scholars were able to read Ancient Egyptian inscriptions and literature confidently. Major advances in the decoding were recognition that the stone offered three versions of the same text (1799); that the demotic text used phonetic characters to spell foreign names (1802); that the hieroglyphic text did so as well, and had pervasive similarities to the demotic (1814); and that phonetic characters were also used to spell native Egyptian words (18221824).

Three other fragmentary copies of the same decree were discovered later, and several similar Egyptian bilingual or trilingual inscriptions are now known, including three slightly earlier Ptolemaic decrees: the Decree of Alexandria in 243 BC, the Decree of Canopus in 238 BC, and the Memphis decree of Ptolemy IV, c. 218 BC. The Rosetta Stone is no longer unique, but it was the essential key to the modern understanding of ancient Egyptian literature and civilisation. The term 'Rosetta Stone' is now used to refer to the essential clue to a new field of knowledge.

Jean-François Champollion (French: [ʒɑ̃ fʁɑ̃swa ʃɑ̃pɔljɔ̃]), also known as Champollion le jeune ('the Younger'; 23 December 1790 – 4 March 1832), 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 mid-teens. As a young man he was renowned in scientific circles, and spoke Coptic, Ancient Greek, Latin, Hebrew and Arabic.

During the early 19th century, French culture experienced a period of 'Egyptomania', brought on by Napoleon's discoveries in Egypt during his campaign there (1798–1801) which also brought to light the trilingual Rosetta Stone. Scholars debated the age of Egyptian civilization and the function and nature of hieroglyphic script, which language if any it recorded, and the degree to which the signs were phonetic (representing speech sounds) or ideographic (recording semantic concepts directly). Many thought that the script was only used for sacred and ritual functions, and that as such it was unlikely to be decipherable since it was tied to esoteric and philosophical ideas, and did not record historical information. The significance of Champollion's decipherment was that he showed these assumptions to be wrong, and made it possible to begin to retrieve many kinds of information recorded by the ancient Egyptians.

Champollion lived in a period of political turmoil in France which continuously threatened to disrupt his research in various ways. During the Napoleonic Wars, he was able to avoid conscription, but his Napoleonic allegiances meant that he was considered suspect by the subsequent Royalist regime. His own actions, sometimes brash and reckless, did not help his case. His relations with important political and scientific figures of the time, such as Joseph Fourier and Silvestre de Sacy helped him, although in some periods he lived exiled from the scientific community.

In 1820, Champollion embarked in earnest on the project of decipherment of hieroglyphic script, soon overshadowing the achievements of British polymath Thomas Young who had made the first advances in decipherment before 1819. In 1822, Champollion published his first breakthrough in the decipherment of the Rosetta hieroglyphs, showing that the Egyptian writing system was a combination of phonetic and ideographic signs – the first such script discovered. In 1824, he published a Précis in which he detailed a decipherment of the hieroglyphic script demonstrating the values of its phonetic and ideographic signs. In 1829, he traveled to Egypt where he was able to read many hieroglyphic texts that had never before been studied, and brought home a large body of new drawings of hieroglyphic inscriptions. Home again he was given a professorship in Egyptology, but only lectured a few times before his health, ruined by the hardships of the Egyptian journey, forced him to give up teaching. He died in Paris in 1832, 41 years old. His grammar of Ancient Egyptian was published posthumously.

During his life as well as long after his death, intense discussions over the merits of his decipherment were carried out among Egyptologists. Some faulted him for not having given sufficient credit to the early discoveries of Young, accusing him of plagiarism, and others long disputed the accuracy of his decipherments. But subsequent findings and confirmations of his readings by scholars building on his results gradually led to the general acceptance of his work. Although some still argue that he should have acknowledged the contributions of Young, his decipherment is now universally accepted and has been the basis for all further developments in the field. Consequently, he is regarded as the "Founder and Father of Egyptology".