Even more ancient are tablets in Linear A, a style of writing used on Crete, and Linear B, employed in Mycenae.
Washington Post(Jun 30, 2016)
Those texts led to the translation of Linear B, and confirmed the identity of Pylos.
National Geographic(Oct 27, 2015)
Linear B was deciphered because the tablets turned out to be in an archaic form of Greek; Mayan glyphs because Mayan languages are still spoken.
Nature(Oct 19, 2015)