It was a slab of granite like rock with the same message crafted on it in three different scripts. The discovery of the stone, called Rosetta Stone, meant that hieroglyphics could be translated
The answer is the Rosetta Stone.
The Rosetta Stone?
The Rosetta stone.
the Rosetta stone was named after the city of Rosetta
It was found by Napoleon's troops near the town of Rosetta in 1799 and, once translated by Champollion, unlocked the language of the hieroglyphs. As to why is was found, that is a philosophical question beyond the scope of this answer.
Rosetta Stone
The Rosetta Stone, discovered in 1799 near Alexandria, was the key to hieroglyphics.
Jean-Francois Champollion unlocked the hieroglyphics in 1821-22. (Thomas Young was his fellow researcher)
French soldiers found the Rosetta stone in the town of Rosetta
The rosetta stone is used to read hierogyphics.
the rosetta stone was founded in 1799
the Rosetta Stone is used for messages