Medieval shipwreck’s cargo revealed by researchers

Around the year 1440, a ship was sailing towards Belgium when it sank off the coast of Sweden. Researchers have now been able to determine its cargo – which included copper, oak timber, quicklime, tar, and bricks and roof tiles – offering insights into trade in northern Europe during the late Middle Ages.

Known as the Skaftö wreck, this ship was discovered by a local diver in 2003, who contacted a museum to tell of finding “mysterious green metal slabs, literally covering the bottom.” Within weeks archaeologists began bringing up artefacts from the shipwreck. Located near the village of Stockevik along Sweden’s western coast, the Skaftö wreck was remarkably well-preserved and had a full cargo. This meant archaeologists needed several years to explore the site, and even now only 15% of the ship has been fully excavated.


The latest study, published in the International Journal of Nautical Archaeology, comes from a team of researchers out of Sweden, Denmark and Germany. They used new methods to analyze the cargo, providing answers about the way trade was conducted in the Middle Ages.

In 2003, the Skaftö wreck was found at the bottom of the sea off Lysekil, north of Gothenburg. The photo shows the Copper ingots. Photo by Jens Lindström / Bohusläns Museum

“The analyses we have carried out give us a very detailed picture of the ship’s last journey and also tell us about the geographical origins of its cargo,” says Staffan von Arbin, a maritime archaeologist at the University of Gothenburg. “Much of this is completely new knowledge for us.”


The cargo consisted of two different types of metal ingots, lime, tar, timber, bricks and roof tiles. The ‘green metal slabs’ turned out to be pieces of copper, which were oval or round-shaped and up to 50 cm in diameter. The new analysis reveals that the copper was mined in two areas in what is currently Slovakia. It was likely then transported from the Carpathian Mountains via river systems down to the coastal town of Gdańsk (Danzig) in Poland.

The analyses also show that the bricks, timber and probably also the tar originated in Poland, while the quicklime is apparently from Gotland. The research reveals many details about these items, including where they were on the Skaftö when it sank. For example:

Bricks and roof tiles are assembled in the northwestern part of the wreck, that is, abaft the centre of the vessel. The total number of bricks could be estimated to perhaps a few hundred, whereas tiles occur more sporadically. From their location on the site, one gets the impression that they must have been stored, if not on the main deck, high up in the hold. Bricks typically measure around 29.5 × 14 × 7.5 cm and recovered specimens weigh approximately 5 kg each. Some of them are broken, or, possibly, cut, in halves. Roof tiles are of the ‘Monk and Nun’ type. None of the tiles observed on the wreck are preserved for their entire length. The best preserved retrieved specimen is 31.5 cm long. It is slightly tapering towards one end, and widths thus vary between 11.5 and 13.7 cm. Bricks and tiles are all made of red-burning clays.

All these cargoes suggest that the shop was coming from Gdańsk, which was a major port of the Hanseatic League. Furthermore, the researchers suggest that it was heading to a port in Western Europe. “We believe that the ship’s final destination was Bruges in Belgium,” says von Arbin. “In the 15th century, this city was a major trading hub. We also know that copper produced in Central Europe was shipped on from there to various Mediterranean ports, including Venice.”

Tobias Skowronek, German Mining Museum, in the process of sampling a copper ingot from the Skaftö wreck. Photo by Staffan von Arbin, University of Gothenburg

Dendrochronological analysis of the ship’s hull reveals that it was built from wood felled between 1437 and 1439, while its timber cargo dates from between 1440 and 1443. This means that the ship was very new when it sank.

The researchers offer this account of its final trip:

Coming from the Baltic Sea, the ship is likely to have headed through the Oresund where dues had to be paid at the Danish Sound Toll in Helsingør, established in 1429. Unfortunately for our case, there are no surviving customs records until the end of that century. From Oresund, the ship continued northwards, probably hugging the now-Swedish west coast, closely. Presumably, the initial plan was to follow the coast to the Agder side of Viken, most probably to the area of Cape Lindesnes on the southwestern tip of Norway, which for many centuries served as a crossroad for overseas traffic. Here, the course would have been set southwards – either to England or to the western European mainland via the Frisian Islands. However, for unknown reasons the journey instead ended abruptly off the island Skaftö.

The article, “Tracing Trade Routes: Examining the Cargo of the 15th-Century Skaftö Wreck,” by Staffan von Arbin, Tobias Skowronek, Aoife Daly, Torbjörn Brorsson, Sven Isaksson and Torben Seir, appears in the International Journal of Nautical Archaeology. Click here to read it. See also the article, “A 15th-Century Bulk Carrier, Wrecked off Skaftö, Western Sweden


See also: Medieval cog discovered off the coast of Sweden

Top Image: Excavation of the Skaftö wreck in 2009. Photo by Staffan von Arbin, Bohusläns Museum