In 1799, during the French Invasion of Egypt, the stone was dug up. It’s carved from basault and is about 45 inches in height.
“On the stone were three parallel inscriptions. The top two, hieroglyphic and demotic were in the Egyptian language; the bottom one was Greek. Although the number of lines of each inscription varied, increasing in each section going down the stone, the three sections of inscriptions were roughly the same size.”
http://www.essortment.com/all/rosettasto…
While the Greek portion was quickly translated the text of the other two languages remained unknown. Parts of the stone were missing and the speaking of ancient Egyptian was lost. One could guess the three texts were the same but that didn’t solve the problem of translating Hieroglyphics. The “key” was when Young noticed that a cartouche (name) corresponded to the Greek name of the Pharaoh Ptolemy. This lead to matching the Hieroglyphics to phonetics and the ability to translate some of the text. Later ,Champollion completed the translation of the writing..
While the stone allowed the Champollion deciphering of Hieroglyphics, the message was quite simple:
“the Rosetta Stone contained a decree from the general council of Egyptian priests issued in 196 BC”
http://www.bbc.co.uk/history/ancient/egy…
http://home.netcom.com/~qkstart/rosetta….
http://www.essortment.com/all/rosettasto…
http://www.bbc.co.uk/history/ancient/egy…
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The Rosetta Stone had three sets of writing, each in a different language. By comparing with one of these languages (which was known) it was possible to learn the other ancient ones and thus opening the way to a lot of other translations.