Swedish archeologists have made an incredible find after discovering cargo and weapons that pirates may have used as part of a ‘dive’ around a 500-year-old shipwreck off Stockholm’s coast.
The remains of the wooden wreckage lie off the coast of Maderö Island and have been dated back to the mid-15th century after the vessel was found at a small Baltic Sea islet southeast of Stockholm.
Long mystified, the Maderö wreck was discovered in 1969 after local divers discovered “a sizeable medieval trading ship filled with bricks.”
However, it wasn’t until May 2022 before an archeology team conducted a full underwater investigation of the ship.
During the ‘deep dive,’ researchers took over 1000 photos of different aspects of the wreckage and published the findings in the International Journal of Nautical Archaeology earlier this month.
Because so little is known about ships from the 15th century, anything scientists can find is precious.
“Not so much is known about the architecture of these ships, so every new wreck that is surveyed increases our knowledge a lot,” according to the study’s co-author Niklas Eriksson, who made a statement to US media.
Samples were then taken from the 15-metre-long oak hull, which lies under 26 metres of water, and were subjected to dendrochronological analysis, a technique that archeologists have used to date the 15th-century Newport and 18th-century Endeavour.
And in November, it was used by archeologists who discovered that the Vikings arrived in the Americas more than 500 years before Christopher Columbus landed in the New World.
Dendrochronology is a word derived from the Greek dendron, ‘tree limb’, Khronos, ‘time’, and -logia; the study consists of analysing tree-ring patterns to identify and date past disturbances such as rockfall events, wildfires or snow avalanches as well as past climate conditions.
Archaeologists successfully determined the timber originated from various locations throughout northern Europe, and at least some of the wood came from a tree felled in 1467.
“The different origin of the wood suggests that the ship came from a shipyard that brought in and imported material from a larger area, rather than relying on locally grown wood,” the researchers said.
Using computer modelling, the researchers visually reconstructed the ship’s hull and the vessel’s cargo, including roof tiles, rectangular bricks, and specialty bricks used to line windows and doors in medieval structures.
After chemical analysis, they could trace the cargo back to Mecklenburg-Vorpommern, a northeastern (modern-day) German state.
“The provenience of the cargo appears a bit surprising in this context as it has been assumed that the domestic production of bricks and tiles could meet the demand of construction works,” archaeologists said.
According to Brendan Foley, a maritime archaeologist at Lund University who was not involved in the study, the foreign-sourced bricks raise questions about medieval trade in the Baltic region.
Their points of origin suggest a link to the Hanseatic League, an organisation of northern German merchant communities that was a powerhouse in interregional trade.
“There is no other cargo apparent on the Maderö wreck, which raises the possibility that it was organic (grain or other foodstuffs, animals, textiles, etc) or something that would not leave a trace,” Foley said.
Although the cargo indicates the vessel sank during a trading voyage, several cannonballs were found onboard, suggesting sailors were prepared for conflict.
Sulphur, an ingredient for gunpowder, was found coating one of the cannonballs, indicating it may have been loaded inside of a cannon at the time the vessel sank.
It’s not clear how common it was for medieval merchant ships to be armed, but it’s possible they took precautions to protect themselves from pirates.
“During the 14th to 15th century, there (was) a lot of piracy on the Baltic Sea,” Ms Eriksson said. At the time, when state-owned navies had not yet been formed, large ships were responsible for supplying goods and defending against attackers.
“At close ranges and under suitable conditions, shot from wrought iron guns could have inflicted casualties on attacking piratical crews,” Foley said.
“These were anti-personnel weapons that could also damage sailing rigs; they were not the hull-crushers of later periods.”
The researchers also determined that, based on its location, the ship had been sailing to Stockholm when it went under, meaning it may have been just a few miles from its destination where it sank.
