The three-age system is the division of human prehistory (with some overlap into the historical periods in a few regions) into three time-periods: the Stone Age, the Bronze Age and the Iron Age, although the concept may also refer to other tripartite divisions of historic time periods. In some systems, a fourth Copper Age is added as between the Stone Age and Bronze Age. The Copper, Bronze and Iron Ages are also known collectively as the Metal Ages.
In history, archaeology and physical anthropology, the three-age system is a methodological concept adopted during the 19th century according to which artefacts and events of late prehistory and early history could be broadly ordered into a recognizable chronology. C. J. Thomsen initially developed this categorization in the period 1816 to 1825, as a result of classifying the collection of an archaeological exhibition chronologically – there resulted broad sequences with artefacts made successively of stone, bronze, and iron.
