The Rosetta Stone has been on display at the British Museum since 1802.
Credit: Vladimir Korostyshevskiy/Shutterstock

Exactly 218 years ago today, on July 19, 1799, French troops in Rosetta, Egypt, uncovered a striking black stone carved with three ancient texts: two Egyptian texts and a Greek one.

The stone, now known as the Rosetta Stone, would be the key to deciphering Egyptian hieroglyphs. It would also land a place in the English language: Today, a search in a scientific journal database for "Rosetta Stone" yields many more metaphorical uses of the term than actual research on the Egyptian artifact. Topics ranging from medical imaging, to black holes, to "intensional dynamic programming" (it's an algorithm thing) have been described as a "Rosetta Stone" by hopeful researchers looking for a breakthrough. [Cracking Codes: 5 Ancient Languages Yet to Be Deciphered]

So what made the Rosetta Stone so special? It wasn't the message it contained. According to the British Museum collections page, the find was part of a larger slab carved with a decree passed by a priestly council affirming Ptolemy V's success as a ruler in 196 B.C., the first anniversary of his coronation. Rather, what made the stone important was how this decree was written: first in Egyptian hieroglyphs; then in demotic, another Egyptian script; and finally, again in ancient Greek.