The Rosetta Stone is a dark granite stone (often incorrectly identified as "basalt") discovered in Rosetta on July 15, 1799 by French Captain Pierre Bouchard while Napoleon was fighting against Great Britain in Egypt. Written on it is a text in Egyptian and Greek, in two languages and three scripts - Egyptian hieroglyphicss, Egyptian demotic script and koine Greek. As the latter script was already known, the stone was the key to deciphering the hieroglyphs in 1822 by Thomas Young and Jean-François Champollion. This led to the translation of other hieroglyphic texts.
The same Ptolemaic decree of 196 BC is written on the stone in the three scripts. The Greek part of the Rosetta Stone begins: Basileuontos tou neou kai paralabontos tén basileian para tou patros... (The new king, having received the kingship from his father...) It is a decree from Ptolemy V, describing various taxes he repealed (one measured in ardebs (Greek artabai) per aroura), and instructing that statues be erected in temples and that the decree be published in the writing of the words of gods (hieroglyphs), the writing of the people (demotic), and the Wynen (Greek; the word is cognate with Ionian) language.