It is often applied to the transition period between the advent of literacy in a society and the writings of the first historians. The preservation of oral traditions may also complicate matters as this can provide a secondary historical source for even earlier events. More recently, colonial sites involving a literate group and a non-literate group , are also studied as protohistoric situations.

In Europe the late Iron Age and Roman periods may be considered protohistoric in most regions as written evidence from locally produced coins and inscriptions as well as passing mentions from classical historians based in the Mediterranean provide some information, but not enough to reconstruct past events satisfactorily.