 Some Tamil-Brahmi inscriptions discovered at Keeladi, Palani, Erode, and Adichanallur, have been claimed to be as ancient as 6th century BC, but so far only the claimed pre-Ashokan inscriptions at Anuradhapura in Sri Lanka have been published academically.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 BC.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.