<P> The three - age system is the categorization of history into time periods divisible by three; for example, the Stone Age, Bronze Age, and Iron Age, although it also refers to other tripartite divisions of historic time periods . In history, archaeology and physical anthropology, the three - age system is a methodological concept adopted during the 19th century by which artifacts and events of late prehistory and early history could be ordered into a recognizable chronology . It was initially developed by C.J. Thomsen, director of the Royal Museum of Nordic Antiquities, Copenhagen, as a means to classify the museum's collections according to whether the artifacts were made of stone, bronze, or iron . </P> <P> The system first appealed to British researchers working in the science of ethnology who adopted it to establish race sequences for Britain's past based on cranial types . Although the craniological ethnology that formed its first scholarly context holds no scientific value, the relative chronology of the Stone Age, the Bronze Age and the Iron Age is still in use in a general public context, and the three ages remain the underpinning of prehistoric chronology for Europe, the Mediterranean world and the Near East . </P>

Who is credited with devising the three-age system