<P> Prehistory is the period of human activity between the use of the first stone tools c. 3.3 million years ago and the invention of writing systems, the earliest of which appeared c. 5,300 years ago . </P> <P> Sumer in Mesopotamia, the Indus valley civilisation and ancient Egypt were the first civilisations to develop their own scripts, and to keep historical records; this took place already during the early Bronze Age . Neighbouring civilizations were the first to follow . Most other civilizations reached the end of prehistory during the Iron Age . The three - age system of division of prehistory into the Stone Age, followed by the Bronze Age and Iron Age, remains in use for much of Eurasia and North Africa, but is not generally used in those parts of the world where the working of hard metals arrived abruptly with contact with Eurasian cultures, such as the Americas, Oceania, Australasia and much of Sub-Saharan Africa . These areas also, with some exceptions in Pre-Columbian civilizations in the Americas, did not develop complex writing systems before the arrival of Eurasians, and their prehistory reaches into relatively recent periods . </P> <P> The period when a culture is written about by others, but has not developed its own writing is often known as the protohistory of the culture . By definition, there are no written records from human prehistory, so dating of prehistoric materials is crucial . Clear techniques for dating were not well - developed until the 19th century . </P> <Dl> <Dd> Beginning </Dd> </Dl>

Prehistory includes the time prior to the use of writing because