Historians who study human societies that developed systems of writing continue to use many of the same types of physical evidence as do those who study societies without writing. For some cultures, the writing or record-keeping systems have not yet been deciphered, so our knowledge of these people also depends largely on physical evidence. Scholars can read the writing of a great many societies, however, adding greatly to what we can learn about them.

Much ancient writing survives only because it was copied and recopied, sometimes years after it was first produced. The survival of a work means that someone from a later period — and often a long chain of someones — judged it worthy of the time, effort, and resources needed to produce copies. The copies may not be completely accurate. Historians studying ancient works thus often try to find as many early copies as they can and compare them to arrive at the version they think is closest to the original.

The works considered worthy of copying tend to be those that are about the political and military events involving major powers, those that record religious traditions, or those that come from authors who were later regarded as important. By contrast, written sources dealing with the daily life of ordinary men and women were few to begin with and were rarely saved or copied because they were not considered significant.

Some early written texts survive in their original form because people inscribed them in stone, shells, bone, or other hard materials, intending them to be permanent. Stones with inscriptions were often erected in the open in public places for all to see, so they include text that leaders felt had enduring importance, such as laws, religious proclamations, decrees, and treaties. Sometimes this permanence was accidental: in ancient Mesopotamia (in the area of modern Iraq), all writing was initially made up of indentations on soft clay tablets, which then hardened. Hundreds of thousands of these tablets have survived, the oldest dating to about 3200 B.C.E., and from them historians have learned about many aspects of everyday life. By contrast, writing in Egypt at the same time was often done in ink on papyrus sheets, made from a plant that grows abundantly in Egypt. Some of these papyrus sheets have survived, but papyrus is much more fragile than hardened clay, so most have disintegrated. In China, the oldest surviving writing is on bones and turtle shells from about 1200 B.C.E., but it is clear that writing was done much earlier on less permanent materials such as silk and bamboo. (For more on the origins of Chinese writing, see “The Development of Writing” in Chapter 4.)