How many versions of a decree issued at Memphis, Egypt was the key to deciphering Egyptian hieroglyphs for the French historian in the early attempts?
Gabriel de La Porte du Theil:  He played a role in the early attempts to decipher the Rosetta Stone. Rosetta Stone: The Rosetta Stone is a granodiorite stele, found in 1799, inscribed with three versions of a decree issued at Memphis, Egypt in 196 BC during the Ptolemaic dynasty on behalf of King Ptolemy V.
three versions