Antoine-Isaac Silvestre de Sacy in the context of "Decipherment of ancient Egyptian scripts"

The writing systems used in ancient Egypt were deciphered in the early nineteenth century through the work of several European scholars, especially Jean-François Champollion and Thomas Young. Ancient Egyptian forms of writing, which included the hieroglyphic, hieratic and demotic scripts, ceased to be understood in the fourth and fifth centuries AD, as the Coptic alphabet was increasingly used in their place. Later generations' knowledge of the older scripts was based on the work of Greek and Roman authors whose understanding was faulty. It was thus widely believed that Egyptian scripts were exclusively ideographic, representing ideas rather than sounds. Some attempts at decipherment by Islamic and European scholars in the Middle Ages and early modern times acknowledged the script might have a phonetic component, but perception of hieroglyphs as purely ideographic hampered efforts to understand them as late as the eighteenth century.

The Rosetta Stone, discovered in 1799 by members of Napoleon Bonaparte's campaign in Egypt, bore a parallel text in hieroglyphic, demotic and Greek. It was hoped that the Egyptian text could be deciphered through its Greek translation, especially in combination with the evidence from the Coptic language, the last stage of the Egyptian language. Doing so proved difficult, despite halting progress made by Antoine-Isaac Silvestre de Sacy and Johan David Åkerblad. Thomas Young, building on their work, observed that demotic characters were derived from hieroglyphs and identified several of the phonetic signs in demotic. He also identified the meaning of many hieroglyphs, including phonetic glyphs in a cartouche containing the name of an Egyptian king of foreign origin, Ptolemy V. He was convinced, however, that phonetic hieroglyphs were used only in writing non-Egyptian words. In the early 1820s Champollion compared Ptolemy's cartouche with others and realised the hieroglyphic script was a mixture of phonetic and ideographic elements. His claims were initially met with scepticism and with accusations that he had taken ideas from Young without giving credit, but they gradually gained acceptance. Champollion went on to roughly identify the meanings of most phonetic hieroglyphs and establish much of the grammar and vocabulary of ancient Egyptian. Young, meanwhile, largely deciphered demotic using the Rosetta Stone in combination with other Greek and demotic parallel texts.

Ustazade Silvestre de Sacy (17 October 1801 – 14 February 1879) was a French journalist. He was born in Paris, the son of the linguist Antoine-Isaac Silvestre de Sacy (1758-1838), who in 1813, was created a baron by Napoleon. His name "Ustazade" means "son of the master" in Persian, presumably due to his father's status as a celebrated orientalist. From 1828 to 1877, he was a literary and political contributor to the Journal des Débats. He became a curator at the Bibliothèque Mazarine in 1836 and became its administrator in 1848. He was elected to the Académie française on 18 May 1854, and became a senator in 1865.