Period: Iron Age and Viking Age (500 BC – 1050 AD)


Project title: Detecting flax retting pits with bioarchaeological markers


Researcher: Sabine Karg, The National Museum of Copenhagen and Copenhagen University & Werner Kofler and Jean Nicoals Haas, Botanical Institute of Innsbruck University, Austria


Email: sabine.karg(at)


Year: 2009





Plant materials, like linen cloth, only rarely survive thousands of years in the ground. But micro biology gives us new possibilities of knowledge of linen production. Preparing the flax plant for linen means retting (semi-rotting) the plants in a pit. This process creates bacteria and the purpose of this experiment is to try to identify the bacteria, which are characteristic for flax-retting. If this is achieved, flax-retting pits can be identified through dirt analysis of the pits, even without visual remains of the plants. This will give us a nuanced impression of where linen was produced and to what extend linen was used in prehistory. Perhaps linen was even as common as wool? And perhaps the production of linen could take the scale of a semi-industry?



The Researchers Conclusions:


In 2009 we have performed the following activities: we succeeded in finding seeds of 2 old landraces of fibre flax -primarily used for linen. The seeds were sown out in late April at The land of Legends Lejre close to the 18th century houses "Krikkebjerg huse”. During the whole summer we spent many hours weeding the small field. In September we had a successful harvest. A riffle bank was constructed and we separated the flax seeds from the flax stems by the help of this bank. At the same time two pits were dug out close to a bog were the groundwater level was high. In one of the pits we placed the harvested flax bundles, while the other remained empty for comparison purposes. Water samples from both pits were systematically taken during the whole summer. The pit with the flax stems started to stink after a few days, most probably caused by growing bacteria and algae. In December 2009 the water and soil samples from both pits are still being analysed at the Botanical Institute of Innsbruck University. We expect that the results will deliver information about the difference of the water quality of the pits. We also expect to find micro-organisms that are specific for flax rotting. We hope to publish the results of this experiment in an international scientific journal.


Reference number HAFF 08/09