Caylus vase

Beyond its historical value as a dynastic artifact of Achaemenid Egypt, its quadrilingual inscription was also the key element in confirming the decipherment of Old Persian cuneiform by Grotefend, through the reading of the hieroglyphic part by Champollion in 1823.

The Old Persian cuneiform inscription in particular, comes first in the series of languages, and reads: 𐎧𐏁𐎹𐎠𐎼𐏁𐎠 𐏐 𐏋 𐏐 𐎺𐏀𐎼𐎣 ( Xšayāršā : XŠ : vazraka)

In 1802, Friedrich Münter realized that recurring groups of characters must be the word for "king" (𐎧𐏁𐎠𐎹𐎰𐎡𐎹, now known to be pronounced xšāyaθiya[check spelling]).

[10] It was only in 1823 that Grotefend's discovery was confirmed, when Jean-François Champollion, who had just deciphered hieroglyphs, had the idea to test his new decipherement technique on the quadrilingual hieroglyph-cuneiform inscription on the famous "Caylus vase" in the Cabinet des Médailles.

[17][18] Saint-Martin attempted to define an Old Persian cuneiform alphabet, of which 10 letters were correct, on a total of 39 signs he had identified.

Champollion had been confronted to the doubts of various scholars regarding the existence of phonetical hieroglyphs before the time of the Greeks and the Romans in Egypt, especially since Champollion had only proved his phonetic system on the basis of the names of Greek and Roman rulers found in hieroglyphs on Egyptian monuments.

[21] In his Précis du système hiéroglyphique published in 1824, Champollion wrote of this discovery: "It has thus been proved that Egyptian hieroglyphs included phonetic signs, at least since 460 BCE".

[23] Until the decipherment of the Caylus phase by Champollion, many uncertainties and competing theories had remained regarding the chronology of Ancient Egyptian history and monuments, due to the lack of positive datation.