New evidence of how the Norse became long-distance mariners

ACCORDING TO THEADAD Saga of Erik the Red, “shipworm will not bore into the wood which has been smeared with the seal-tar”. Viking scholars debate the precise meaning of “seal” in “seal-tar”. One interpretation is that the Scandinavian conquerors mixed tar, or pitch, with animal fat and some experiments suggest this may indeed keep shipworm at bay. What is clear is that tar was an important marine technology, and new finds suggest that a vast industry making it emerged at the beginning of the Viking era, helping enable their conquests.The oldest tar pits in Sweden date from around 100 to 400. The first were discovered in the early 2000s, and are found close to old settlements, suggesting that the tar was for coating houses and household items. It was made by stacking pine wood into conical pits a metre or two across, setting the wood on fire and covering it with turf and charcoal to encourage a slow combustion. In this way, the wood’s resin would turn to tar and drip out of the cone’s bottom into a buried container.