The earliest undisputed deciphered epigraphy found in India are the Edicts of Ashoka of the 3rd century BCE, in the Brahmi script. If epigraphy of proto-writing is included, undeciphered markings with symbol systems that may or may not contain linguistic information, there is substantially older epigraphy in the Indus script, which dates back to the early 3rd millennium BCE. Two other important archeological classes of symbols are found from the 1st millennium BCE, Megalithic graffiti symbols and symbols on punch-marked coins, though most scholars do not consider these to constitute fully linguistic scripts, and their semiotic functions are not well understood.