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.
Celts
The Proto-Celtic language is usually dated to the Late Bronze Age. The earliest records of a Celtic language are the Lepontic inscriptions of Cisalpine Gaul (Northern Italy), the oldest of which predate the La Tène period. Other early inscriptions, appearing from the early La Tène period in the area of Massilia, are in Gaulish, which was written in the Greek alphabet until the Roman conquest. Celtiberian inscriptions, using their own Iberian script, appear later, after about 200 BC. Evidence of Insular Celtic is available only from about 400 AD, in the form of Primitive Irish Ogham inscriptions.