Writing system
Writing systems were preceded by proto-writing, systems of ideographic and/or early mnemonic symbols. The best known examples are:The invention of the first writing systems is roughly contemporary with the beginning of the Bronze Age in the late Neolithic of the late 4th millennium BC. The Sumerian archaic cuneiform script and the Egyptian hieroglyphs are generally considered the earliest writing systems, both emerging out of their ancestral proto-literate symbol systems from 3400 to 3200 BC with earliest coherent texts from about 2600 BC. It is generally agreed that Sumerian writing was an independent invention; however, it is debated whether Egyptian writing was developed completely independently of Sumerian, or was a case of cultural diffusion.
Early Indian epigraphy
The earliest traces of epigraphy in the Indian Subcontinent are found in the undeciphered inscriptions of the Indus Valley Civilization (Indus script), which date 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. The earliest deciphered epigraphic inscriptions of significant length are the Edicts of Ashoka of the 3rd century BCE, written in forms of Prakrit in the Brahmi script. Samanam inscriptions in South India written in Tamil-Brahmi, Bhattiprolu alphabet and the Kadamba alphabet are also of relatively early date. Some Tamil-Brahmi inscriptions discovered at Palani, Erode, and Adichanallur, have been claimed to be as ancient as 500 BCE, but so far only the claimed pre-Ashokan inscriptions at Anuradhapura in Sri Lanka have been published academically.