The three-age system is the periodization of history into three time periods;[better source needed] for example: the Stone Age, the Bronze Age, and the 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.
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.
The structure reflects the cultural and historical background of Mediterranean Europe and the Middle East and soon underwent further subdivisions, including the 1865 partitioning of the Stone Age into Paleolithic, Mesolithic and Neolithic periods by John Lubbock. It is, however, of little or no use for the establishment of 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.
Their cause, he asserts, is "the industry of our forefathers (l'industrie de nos premiers pères)." He adds later that bronze and iron implements imitate the uses of the stone ones, suggesting a replacement of stone with metals. Mahudel is careful not to take credit for the idea of a succession of usages in time but states: "it is Michel Mercatus, physician of Clement VIII who first had this idea". He does not coin a term for ages, but speaks only of the times of usages. His use of l'industrie foreshadows the 20th century "industries," but where the moderns mean specific tool traditions, Mahudel meant only the art of working stone and metal in general.
In 1816 Thomsen at age 27 was appointed to succeed the retiring Rasmus Nyerup as Secretary of the Kongelige Commission for Oldsagers Opbevaring ("Royal Commission for the Preservation of Antiquities"), which had been founded in 1807. The post was unsalaried; Thomsen had independent means. At his appointment Bishop Münter said that he was an "amateur with a great range of accomplishments." Between 1816 and 1819 he reorganized the commission's collection of antiquities. In 1819 he opened the first Museum of Northern Antiquities, in Copenhagen, in a former monastery, to house the collections. It later became the National Museum.
Like the other antiquarians Thomsen undoubtedly knew of the three-age model of prehistory through the works of Lucretius, the Dane Vedel Simonsen, Montfaucon and Mahudel. Sorting the material in the collection chronologically ("Royal Commission for the Preservation of Antiquities"), which had been founded in 1807. The post was unsalaried; Thomsen had independent means. At his appointment Bishop Münter said that he was an "amateur with a great range of accomplishments." Between 1816 and 1819 he reorganized the commission's collection of antiquities. In 1819 he opened the first Museum of Northern Antiquities, in Copenhagen, in a former monastery, to house the collections. It later became the National Museum.
Like the other antiquarians Thomsen undoubtedly knew of the three-age model of prehistory through the works of Lucretius, the Dane Vedel Simonsen, Montfaucon and Mahudel. Sorting the material in the collection chronologically he mapped out which kinds of artifacts co-occurred in deposits and which did not, as this arrangement would allow him to discern any trends that were exclusive to certain periods. In this way he discovered that stone tools did not co-occur with bronze or iron in the earliest deposits while subsequently bronze did not co-occur with iron - so that three periods could be defined by their available materials, stone, bronze and iron.
To Thomsen the find circumstances were the key to dating. In 1821 he wrote in a letter to fellow prehistorian Schröder:
nothing is more important than to point out that hitherto we have not paid enough attention to what was found together.
and in 1822:
we still do not know enough about most of the antiquities either; ... only future archaeologists may be able to decide, but they will never be able to do so if they do not observe what things are found together and our collections are not brought to a greater degree of perfection.
This analysis emphasizing co-occurrence and systematic attention to archaeological context allowed Thomsen to build a chronological framework of the materials in the collection and to classify new finds in relation to the established chronology, even without much knowledge of their provenience. In this way, Thomsen's system was a true chronological system rather than an evolutionary or technological system. Exactly when his chronology was reasonably well established is not clear, but by 1825 visitors to the museum were being instructed in his methods. In that year also he wrote to J.G.G. Büsching:
To put artifacts in their proper context I consider it most important to pay attention to the chronological sequence, and I believe that the old idea of first stone, then copper, and finally iron, appears to be ever more firmly established as far as Scandinavia is concerned.
By 1831 Thomsen was so certain of the utility of his methods that he circulated a pamphlet, "Scandinavian Artifacts and Their Preservation, advising archaeologists to "observe the greatest care" to note the context of each artifact. The pamphlet had an immediate effect. Results reported to him confirmed the universality of the Three-age System. Thomsen also published in 1832 and 1833 articles in the Nordisk Tidsskrift for Oldkyndighed, "Scandinavian Journal of Archaeology." He already had an international reputation when in 1836 the Royal Society of Northern Antiquaries published his illustrated contribution to "Guide to Scandinavian Archaeology" in which he put forth his chronology together with comments about typology and stratigraphy.