Here’s what you’ll learn when you read this story:

• Underwater archaeologists discovered a shipwreck off the coast of Spain from the 17^th century—and more importantly, the ship’s contents.
• Research into the cargo on the Delta 1 wreck shows that it held items from all across Europe.
• Experts believe that the mix of items found on the ship point to black market trade in the Bay of Cadiz.

When underwater archaeologists discovered the Delta I shipwreck off the coast of Cadiz, Spain, in 2024, they knew they’d uncovered the remains of a 17^th-century vessel. But they hadn’t yet gotten the full picture of the cargo the ship has held underwater for over 300 years. Those details are just now coming to light, revealing a secret trade network from Sweden to Bolivia.

Discovered during dredging work ahead of construction on a new ship terminal, archaeologists with the Center of Underwater Archaeology of the Andalusian Institute of Historical Heritage have since investigated the ship, which is still stuck in the murky grime of the Port of Cadiz.

So far, teams have reported 27 Swedish Finbanker iron cannons (in a vast range of working orders), a bronze bell with an unknown provenance (featuring the inscription “Jesus, Maria y Jose 1671”), and at least 18 silver ingots that experts believe came from mines in what is now Bolivia. The collection represents a vast trade network far outside the norms of Spanish merchants, and is likely evidence of a black market running up and down Europe’s Atlantic Coast.

While much of the history of the ship isn’t known—though it was named Delta I following the 2024 find, the official name remains a mystery—experts believe the vessel was likely built in France and employed by Dutch traders, who were known to frequent the cannon markets during the height of the 17^th century, according to a translated report published by Cadiz Directo.

While the cannons were Swedish, they may have actually served as French naval artillery. The 27 found aboard the shipwreck comprised five different calibers and were all in differing states of preservation, with some having been rendered unusable thanks to missing components or damage to the muzzles. Experts believe the wayward cannons could have encountered a variety of fates—they may have served as ballast for the ship, or could have been damaged right before the ship’s demise.

Deeper understanding of the cannons, unfortunately, may be out of reach to modern investigators. The latest study states that the cannons likely shifted during the port’s dredging, which would have “decontextualized” the site and destroyed evidence.

The 18 silver ingots are interesting of their own accord, weighing half a ton in total. While initial find reports called out 22 silver ingots, the latest study states that there were only 18, one of which is clearly inscribed with the date 1667. This is where the contraband theory comes most heavily into play: Spain taxed precious metals mercilessly, leading experts to suggest that the presence of silver and foreign cannons on the same wreck implies trade outside official channels.

“The trade in precious metals was heavily supervised by the Spanish administration and, despite the fact that Seville held the monopoly, Cadiz, due to its unbeatable natural conditions, was also used for the loading and unloading of galleons from America,” archaeologists Ernesto Toboso Suárez and Josefa Martí Solano wrote in a study presented at the First Ibero-American Congress of Nautical and Underwater Archaeology (CIANYS 2021).

That made the Bay of Cadiz a likely hotbed for smuggling amidst a bustling maritime trade.

Finding further answers may be difficult, but not for a lack of trying. Researchers hope that 3D modeling of the ship and detailed timber analysis will narrow down the ship’s history even further, offering more insight into a shipwreck filled with questionable cargo.