A small, muzzle-loading cast copper-alloy cannon that was found in the sea off Marstrand on the Swedish west coast and dates back to the 14th century has been identified as Europe’s – most likely – oldest shipboard cannon.
The artifact, however, was not up to standard.
In a recent study published in the journal The Mariner’s Mirror, researchers from the University of Gothenburg note that the cannon’s copper alloy contains about 14 weight percent lead and only small amounts of tin.
Using 3D scanning and chemical analysis of the metal used to cast the cannon, the experts concluded that the alloy is far from optimal and it is likely that the cannon would have cracked and been rendered unusable if used intensively for long periods.
“Clearly, the person who cast the cannon did not have the necessary knowledge and understanding of the properties of various copper alloys,” archaeologist Staffan von Arbin said in a media statement. “This shows that the noble art of cannon casting had not yet been fully mastered at that time, and that production was largely based on trial and error.”
According to von Arbin, the analysis also indicates that the copper ore used in the cannon’s production was mined in present-day Slovakia, while the lead probably came from England or the border region between Poland and the Czech Republic.
The researcher explained that in the 14th century, the town of Marstrand, famous for its excellent port, was an important hub for commercial shipping between Western Europe and the Baltic Sea area. But the sea was also an arena for war and conflict, and coastal civilian populations were often hit hard. In addition, there was always a risk of attacks by pirates.
Funnel-shaped cannons of the Marstrand cannon type are usually attributed to the 15th–16th centuries, but this find is testimony to the fact that this model already existed in the 14th century. The preserved remains of the charge in the cannon’s powder chamber also show that the use of cartouches, a kind of textile packaging for the powder charge, came into use much earlier than previously known.
The remaining charge is what gave away the artifact’s age as it was possible to use it for radiocarbon dating.
The powder also allowed the researchers to conclude that it was a shipboard cannon and not a cannon that was being transported as cargo. This means the cannon was loaded and ready for use in combat at the time it ended up on the sea floor.
“Now, of course, we also want to try to locate and document the ship that the cannon belonged to. Although it is probably severely degraded and broken up, it should be possible to find scattered remains of the wreck if we conduct a thorough inventory of the site and its surroundings,” von Arbin said.
