The three-age system is the periodization of human pre-history (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 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. The system appealed to British researchers working in the science of ethnology – they 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 modern scientific value, the relative chronology of the Stone Age, the Bronze Age and the Iron Age remains in use in a general public context, and the three-ages concept underpins prehistoric chronology for Europe, the Mediterranean world and the Near East. The structure reflects the cultural and historical background of Mediterranean Europe and the Middle East. It soon underwent further subdivisions, including the 1865 partitioning of the Stone Age into Palaeolithic, Mesolithic and Neolithic periods by John Lubbock. The schema, however, has little or no utility for establishing chronological frameworks in sub-Saharan Africa, much of Asia, the Americas and some other areas; and has little importance in contemporary archaeological or anthropological discussion for these regions. Origin The concept of dividing pre-historical ages into systems based on metals extends far back in European history, probably originated by Lucretius in the first century BC. But the present archaeological system of the three main ages – stone, bronze and iron – originates with the 19th century Danish archaeologist Christian Jürgensen Thomsen, who placed the system on a more scientific basis by typological and chronological studies, at first, of tools and other artifacts present in the Museum of Northern Antiquities in Copenhagen (later the National Museum of Denmark). He later used artifacts and the excavation reports published or sent to him by Danish archaeologists who were doing controlled excavations. His position as curator of the museum gave him enough visibility to