• Two 18th-century shipwrecks off Costa Rica have been identified as the Danish slave ships Fridericus Quartus and Christianus Quintus.
• Archaeological evidence, including wood samples, yellow bricks, and clay pipes, confirms the ships' origin and purpose.
• The discovery sheds light on Denmark's role in the transatlantic slave trade and provides a tangible link to a dark chapter in history.

Two shipwrecks located off the coast of Costa Rica's Cahuita National Park, long thought to be pirate ships, have been identified as the Danish slave ships Fridericus Quartus and Christianus Quintus. The ships sank in 1710. An underwater excavation in 2023, involving the analysis of wood, bricks, and clay pipes, confirmed their origin and purpose, providing insights into Denmark's involvement in the transatlantic slave trade. The discovery marks a significant moment in maritime archaeology and Danish history.

• What: Identification of two 18th-century shipwrecks, Fridericus Quartus and Christianus Quintus, as former Danish slave ships. The ships wrecked in 1710.
• Who: National Museum of Denmark, marine archaeologists David Gregory and Andreas Kallmeyer Bloch, University of Southern Denmark, American marine archaeologists (in 2015).
• When: Shipwrecks occurred in 1710. Excavation took place in 2023. Identification confirmed recently.
• Where: Shallow waters off Costa Rica's Cahuita National Park.

The identification of the Fridericus Quartus and Christianus Quintus as Danish slave ships represents a significant archaeological find. The initial misidentification of the wrecks as pirate ships highlights the challenges of maritime archaeology and the importance of thorough investigation. The evidence, including wood dating, brick analysis, and historical records, strengthens the conclusion. This discovery sheds light on Denmark's role in the transatlantic slave trade, a history that Denmark banned in 1792, but did not abolish until 1847. This provides valuable insight into a less-discussed aspect of colonial history.

"The analyses are very convincing and we no longer have any doubts that these are the wrecks of the two Danish slave ships. The bricks are Danish and the same goes for the timbers, which are additionally charred and sooty from a fire. This fits perfectly with the historical accounts stating that one of the ships burnt."

"This is undoubtedly the craziest archaeological excavation I’ve yet been part of. Not only because it matters greatly to the local population, but also because it’s one of the most dramatic shipwrecks in the history of Denmark, and now we know exactly where it happened."

The identification of the Fridericus Quartus and Christianus Quintus as Danish slave ships provides closure to a long-standing mystery and offers valuable insights into Denmark's colonial past. The archaeological evidence, combined with historical records, paints a clear picture of the ships' origin and purpose. This discovery not only contributes to our understanding of maritime history but also serves as a reminder of the human cost of the transatlantic slave trade. Further research and excavation efforts may reveal additional details about the ships' voyages and the lives of those who were enslaved.