Christian Jürgensen Thomsen, a Danish antiquarian, was born Dec. 29, 1788. Thomsen was a businessman and an aggressive collector of antiquities; he was not a historian, or even an academic, when he was appointed secretary of the Royal Commission for the Preservation of Antiquities in 1816. However, he was very good at his job, and by 1819 he had brought all of the antiquities in his care under one roof, as the Royal Museum of Nordic Antiquities, with himself as effective curator.

When the Museum finally settled into the Royal Castle Christiansborg in 1832, Thomsen proceeded to implement a novel classification scheme. Traditionally, museums of antiquities were curated by historians, who tended to impose their own particular views of history onto the objects within their care. Thomsen took quite a different approach; he decided to let the objects speak for themselves. He didn’t pay any attention to where they were found; he was more concerned with their material composition, the manner of their production, and their intended use. As he arranged the artifacts in the Museum, he found they sorted themselves into three broad classes; those made of stone, those made of copper or bronze, and those made of iron. Moreover, it appeared from the details of manufacture that the iron tools and objects were made most recently, preceded by the bronze tools, with the stone tools and objects being the oldest. Therefore they represented the productions of three different and successive ages: the Stone Age, the Bronze Age, and the Iron Age. Thomsen did not invent the terms, but he was the first to use them as the basis for a museum classification system, and it was through Thomsen that they became widespread.

The rest of the world learned about Thomsen’s three-age system when he published an essay in a Danish booklet, Ledetraad til nordisk oldkyndighed (A Guidebook to Nordic Antiquities) in 1836. The book was translated into German in 1837 and into English (as Guide to Northern Archaeology) in 1848. It marks the beginning of modern archaeological classification practices. We have long held the German and English editions in our History of Science Collections, but only this year did we acquire the original Danish Ledetraad (second image), so it seems appropriate to celebrate his birthday this year as well.

The Museum of Nordic Antiquities was transformed into the National Museum of Denmark in 1891. There is an attractive oil portrait of Thomsen in the National Museum, reproduced here (third image). The woodcut above (first image) was printed in 1846 and depicts Thomsen guiding some visitors through his museum.

Dr. William B. Ashworth, Jr., Consultant for the History of Science, Linda Hall Library and Associate Professor, Department of History, University of Missouri-Kansas City. Comments or corrections are welcome; please direct to