How it began
Christian Jurgensen Thomsen, born in Copenhagen in 1788, came to antiquities through the study of coins. In 1819 he became the first curator of what is now the National Museum of Denmark. In 1836 he edited and published in Copenhagen a guidebook to the museum, Ledetraad til Nordisk Oldkyndighed, in which he classified the collections by whether objects were made of stone, bronze or iron and argued that these groups were three successive ages. Museum collections were arranged for aesthetic or thematic appeal and gave no clear sense of time order. Thomsen saw that the collection needed systematic organization for the sake of chronology.
How it works
Thomsen defined the Age of Stone as the period when tools and weapons were of stone, wood or bone and metals were little known, the Age of Bronze as the time of copper or bronze cutting tools, and the Age of Iron as the last period, when iron replaced bronze. He reasoned from "closed finds," noting which kinds of objects, styles and decoration were found together, which let him set out the usual associations for each period.
How it spread
Thomsen's assistant, the archaeologist Jens J. A. Worsaae, later demonstrated through fieldwork that stone, bronze and iron layers followed one another in the ground in Denmark. An English translation of the guide by the Earl of Ellesmere was published in 1848.
What lasted
A historian quoted by the History of Information site calls the system the basic chronology that now underpins the archaeology of most of the Old World. Its principles of classification, time order and analysis of materials continue to shape how curators and historians arrange collections.
