Civilizations record their history, but how do we derive information for periods before record keeping started? How much do we know for that era of human civilization?
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The invention of writing, roughly in the 4th millennium BC divides human history in two major periods:
The divide isn't uniform for all civilizations, obviously not all civilizations invented writing at the same time. Furthermore some ancient civilizations, although they thrived in a period that's generally considered part of recorded history, didn't really do a great job recording their own history. For example, in Ancient Sparta, record keeping and any kind of written history was forbidden by law. In such cases, most of the information we have are from neighbouring civilizations.
Prehistory is distinctively different than recorded history, all the information we have for prehistoric times comes from remains and artefacts. Archaeologists studying the prehistoric era of a civilization utilize a vast array of interdisciplinary techniques, such as the study of geologic records and fossils, techniques that are more commonly associated with palaeontology and geology.