Maritime archaeologists in Denmark have discovered a gargantuan medieval ship off the coast of Copenhagen.
The vessel, named Svaelget 2, is the world’s largest known cog—a merchant ship in the Middle Ages (another term for the medieval era) that revolutionized trade. Its extraordinary preservation is shedding light not just on the ship and its trade context, but on the lives of those that sailed aboard it.
Svaelget 2 is around 92 feet (28 meters) long, 19.7 feet (6 meters) high, and 29.5 feet (9 meters) wide. It was probably capable of hauling 300 tons of cargo, according to the team’s estimates. The existence of this ship hints at a fixed, consistent system of trade throughout Northern Europe.
“A ship with such a large cargo capacity is part of a structured system where merchants knew there was a market for the goods they carried. Svælget 2 is a tangible example of how trade developed during the Middle Ages,” Otto Uldum, excavation leader and maritime archaeologist at the Viking Ship Museum in Denmark, said in a museum statement. What’s more, “It required a society that could finance, build and equip these enormous ships that served the Middle Ages’ need for export and import over great distances.”
An efficient vessel
Cogs represent a pivotal maritime technological advancement. With origins in the North Sea region, cogs enabled the efficient and cheap transportation of large amounts of products and played a crucial role in the 14th and 15th centuries’ economic progress.
A crew of strikingly few individuals was able to sail these vessels, even though they were the medieval era’s largest merchant ships. Their ability to carry massive amounts of cargo revolutionized trade dynamics; common merchandise, not just luxury goods, could now enter long-distance commerce. Large cogs were constructed to travel from the Netherlands, around the Skagen (the northern tip of Denmark), through the Sound (the strait between Denmark and Sweden), and to the Baltic merchant towns.
“It is clear evidence that everyday goods were traded. Shipbuilders went as big as possible to transport bulky cargo—salt, timber, bricks or basic food items,” Uldum explained. “The cog revolutionised trade in Northern Europe. It made it possible to transport goods on a scale never seen before.”
Svaelget 2’s wood dates back to approximately 1410 and comes from the Netherlands and Pomerania (a historical region including parts of modern-day Poland and Germany). Its composition—Pomeranian planks and Dutch frames—points to vast amounts of timber traveling through Northern Europe. According to Uldum, it reveals that Pomeranian wood traveled to the Netherlands, where the necessary shipbuilding expertise was found.
More comfortable than Viking Age ships
The shipwreck’s unprecedented preservation includes never-seen-before remains of its rigging, according to the archaeologist, shedding new light on cogs’ sailing equipment.
“The finds show how something as complex as the rigging was solved on the largest cogs. Rigging is absolutely central to a medieval ship, as it makes it possible to control the sail, secure the mast and keep the cargo safe. Without ropes and rigging, the ship would be nothing,” the maritime archaeologist explained.
What’s more, the ship’s discovery confirms medieval cog features previously seen in illustrations but never confirmed by strong archaeological evidence: wooden platforms at the ship’s bow (front) and stern (back) called high castles. Specifically, a large part of the sterncastle, a covered deck for the crew, has survived.
“We have plenty of drawings of castles, but they have never been found because usually only the bottom of the ship survives. This time we have the archaeological proof,” said Uldum. “It is not comfort in a modern sense, but it is a big step forward compared to Viking Age ships, which had only open decks in all kinds of weather.”
Cooking on the sea
Further notable discoveries include the galley (where people could cook with an open fire) built from bricks and tiles and nearby ceramic bowls, bronze cooking pots, and fish and meat remains. This is the first brick galley in a medieval ship found in Denmark’s waters, said Uldum. It is evidence of surprising levels of organization and comfort; sailors could enjoy hot meals on the water. The team also found shoes, painted wooden dishes, combs, and rosary beads.
“The sailor brought his comb to keep his hair neat and his rosary to say his prayers. We have the remains of the pots his food was cooked in and the bowls he ate from. These personal objects show us that the crew brought everyday items with them. They transferred their life on land to life at sea,” said Uldum.
At least one mystery remains, however. What was Svaelget 2’s cargo? Only things that could have belonged to the crew or were part of the ship’s gear have emerged. Because the vessel’s hold wasn’t covered, certain goods would have or might have drifted off while the ship sank, and the lack of a ballast (material used to stabilize a ship) indicates that Svaelget 2 was packed with a heavy cargo. One thing is certain—it was a trade ship. The team hasn’t identified any evidence of military activity.
Ship-powered trade
“Perhaps the find does not change the story we already know about medieval trade. But it does allow us to say that it was in ships like Svælget 2 that this trade was created. We now know, undeniably, that cogs could be this large—that the ship type could be pushed to this extreme,” Uldum concluded. “Svælget 2 gives us a tangible piece of the puzzle and makes it possible to understand how technology and society evolved side by side in an era when shipping was the driving force behind international trade.”
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