How did the Rosetta Stone unlock Egyptian hieroglyphs?

The Rosetta Stone carries one decree in three scripts: hieroglyphs, Demotic and ancient Greek. Because scholars could still read Greek, the stone gave them a parallel text to compare against the Egyptian. Thomas Young first showed that some hieroglyphs spelled the sounds of a royal name, and Jean-François Champollion then worked out that the script recorded the sounds of the Egyptian language more broadly. The stone was a key, but the decipherment took years of further work. [1] [2]

The stone records a decree issued by Ptolemy V in 196 BC. According to the British Museum, the hieroglyphs were the sacred script suited to a priestly decree, Demotic was the cursive script used for daily purposes, and Greek was the language of Egypt's Greco-Macedonian rulers. Hieroglyphic knowledge had vanished soon after the end of the 4th century AD, so nobody could read the Egyptian text when the stone was found. The Greek was translated immediately. [1] [2]

Smithsonian Magazine describes how Young focused on hieroglyphs enclosed in oval frames called cartouches. The Greek text showed that the name Ptolemy appeared repeatedly, and Young found matching cartouches in the hieroglyphic text. He reasoned that foreign names would be hard to write with symbols for ideas, so hieroglyphs could be phonetic in such cases. He published his findings in 1819, but his progress stalled because he did not accept that hieroglyphs could represent sounds outside foreign names. [3]

Champollion improved Young's readings of Greek and Roman rulers' names by assigning one sound to each sign. The British Museum notes that he counted 1,419 hieroglyphic signs on the stone against 486 Greek words, and concluded that the script could not be purely ideographic. He identified determinatives, signs that indicate the kind of word, and showed that phonetic and non-phonetic signs could be mixed. [4]

He then found phonetic signs in the cartouches of the New Kingdom pharaohs Ramesses and Thutmose. He used Coptic, a later form of Egyptian written in the Greek alphabet, to recognise the sun disc as the word ra. The British Museum says one sign was misread in this process: a sign he took as m is in fact the two-consonant sign ms. Egyptologist James Allen, quoted by Smithsonian Magazine, said Coptic let Champollion work out sound values by matching hieroglyphs to the Greek translation. [4] [3]

Champollion presented his results to the Académie des Inscriptions et Belles Lettres in Paris on 27 September 1822, with his rival Young in the audience. The British Museum describes this as the birth of Egyptology. [1] [4]