500-year-old Danish-Norwegian flagship Gribshunden reveals medieval naval power. Archaeologists uncover rare artillery, explosion evidence, and King Hans’ floating castle, offering a glimpse into Europe’s early maritime dominance and Baltic politics.
Off the Swedish coast, the wreck of a 500-year-old royal warship has revealed a remarkable story of ambition, technology, and power. The Danish-Norwegian flagship Gribshunden, lost in 1495, was more than a vessel—it was King Hans’ floating castle, a symbol of military might and diplomatic authority in the late Middle Ages. Recent archaeological work by Lund University offers a rare glimpse into how the seas were conquered, not with diplomacy alone, but with guns and firepower.
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Diving Into History
“Diving on this late medieval royal shipwreck is of course exciting. However, the greatest satisfaction is when we can actually put the pieces of the puzzle together later on; combining Martin’s castle expertise with Kay’s deep understanding of artillery,” explains Brendan Foley, the marine archaeologist behind the study.
Foley, alongside Lund University archaeologist Martin Hansson and medieval artillery expert Kay Douglas Smith, has uncovered details about the ship’s small-calibre guns—designed for close-range combat and boarding actions—that showcase a technological leap for Europe’s naval power.
The discovery is extraordinary. Gribshunden is the only known shipwreck of its kind from the medieval period, and it mirrors the artillery and construction of vessels used by early explorers like Columbus and Vasco da Gama.
A Floating Castle for King Hans
Built near Rotterdam between 1483 and 1484, Gribshunden was a significant investment—absorbing around 8% of Denmark’s national budget at the time. But King Hans of Denmark and Norway used it not for exploration, but to solidify his rule.
Hans sailed the ship frequently, visiting Sweden, Gotland, and Norway. The flagship functioned like a terrestrial royal fortification at sea, blending military might with diplomacy, social influence, and cultural presence.
“It was his floating castle,” Foley says. “It allowed him to project power, not just through its guns, but through its very presence in the Baltic waters.”
Fire, Explosion, and a Sudden End
Gribshunden’s career was cut short after about a decade of service. The ship sank mysteriously in 1495 off Ronneby, Sweden, during a royal voyage. Historical accounts suggest that while Hans was ashore, an explosion and fire erupted aboard the ship.
Among the 22 lead artillery shots recovered from the wreck, some are flattened on one or two sides—a likely result of the detonation. “Shot stored in the hold near the gunpowder ricocheted inside the ship,” researchers note, providing a tangible connection to the disaster that ended the flagship’s life.
Denmark’s Untapped Global Ambitions
With ships like Gribshunden and its arsenal, Denmark had the tools to compete in global exploration. Vikings and medieval Norse had already settled in Iceland, Greenland, and even parts of North America. With Hans’ warship technology, European-style expansion could have been within reach.
Yet, Denmark remained focused on consolidating the Baltic region. Papal authority also played a role: a 1493 bull granted Spain rights to the Americas, and treaties with Portugal ceded the Indian Ocean to Iberian powers. Ignoring these papal directives carried a real risk of excommunication.
Unveiling the Arsenal
The Lund University team has digitally recreated the guns from Gribshunden, offering an unprecedented look at late medieval artillery. Of the ship’s original 50 or more guns, artifacts from 11 have been recovered so far.
“Examining these weapons gives us insight into how naval combat worked at the time,” Foley says. “They were designed to injure or kill enemy personnel, paving the way for boarding actions and capturing ships—a very hands-on kind of warfare.”
Preserving the Past
The Gribshunden artifacts are housed at Blekinge Museum in Rosenholm, with temporary displays in Ronneby and Helsingor, Denmark. Plans are underway to create a dedicated Gribshunden museum in Ronneby, ensuring that the story of this floating castle—and its role in shaping Europe’s naval power—is preserved for future generations.
“This is not just a shipwreck,” Foley emphasizes. “It’s a window into the world of late medieval kings, explorers, and warriors—a time when the seas were as much a battleground as the lands they ruled.”
Source: Taylor & Francis