written in Old Persian, Elamite, and Babylonian, the Behistun Inscription by King Darius did for cuneiform what the Rosetta Stone did for Egyptian hieroglyphs. Scholars were able to first decipher the cuneiform of the Old Persian part of the inscription and use that to make sense of the Elamite and Babylonian portions
I have a fairly extensive file on the Behistun Inscription. {Wikipedia once posted a translation of the inscription - which is in my file - but now they link to: https://web.archive.org/web/20090413214509/http://mcadams.posc.mu.edu/txt/ah/Persia/Behistun_txt.html - which is similar to my archived translation.}
If such finds as this acted as a 'Rosetta Stone' why is Elamite still so unread?