There has been a small online tidal wave in the past week. It concerns an article in the academic journal PNAS. Admittedly, it is a fascinating study. In short, researchers examined preserved cod dating back to the Viking Age. This evidence comes from the trading town of Haithabu (or Hedeby) and turns out to be imported from Lofoten, Norway.
The story is spectacular because DNA-research has helped to determine the origin of the cod to the Lofoten. Secondly, it confirms a long-standing theory of ancient trading routes going as far as the arctic regions. The clue about their existence comes from the description of Ohthere of Hålogaland. He was a trader from this particular area, who travelled to Haithabu and as far as the court of King Alfred the Great.
The advantage of medieval fishing in Lofoten is an abundance of this type of cod in the area, especially during the seasonal mating period. Furthermore, the climate allows for quick freeze-drying instead of using (expensive) salt. The increase in medieval towns and population in northern Europe ensured that the quantity and quality of this preserved cod found its way to trading centres, such as Haithabu.