Scholars make a reasonable distinction between prehistory and history of early writing, but have disagreed concerning when prehistory becomes history and when proto-writing became "true writing". The definition is largely subjective. Writing, in its most general terms, is a method of recording information and is composed of graphemes, which may in turn be composed of glyphs.
The emergence of writing in a given area is usually followed by several centuries of fragmentary inscriptions. Historians mark the "historicity" of a culture by the presence of coherent texts in the culture's writing system(s).
The invention of writing was not a one-time event, but a gradual process initiated by the appearance of symbols, possibly first for cultic purposes.