600 meters deep off Cartagena, Colombian researchers explored what could be one of the most important underwater archaeological sites ever documented. On the seabed rest dozens of irregular gold coins, struck by hand, associated with colonial artefacts dating from the beginning of the 18th century. Would it be San José?
Their analysis, led by Daniela Vargas Ariza of the Naval School of Cadets Almirante Padilla and the Colombian Institute of Anthropology and History (ICANH), was published on June 10, 2025 in the journal Antiquity. The numismatic characteristics of these currencies, crossed with historical sources, have been pointing towards an expected conclusion for decades: the formal identification of the Spanish Galion San José, sunk in 1708 while it was carrying a colossal treasure to Europe. A discovery that reactivates major archaeological, political and economic issues.
The San José, a mythical wreck finally identified?
San José was the flagship of the Indies fleet. The Spanish crown had responsible for repatriating the riches extracted from its American colonies to Europe. On June 8, 1708, off the coast of Cartagena, this heavily armed galleon and responsible for a considerable treasure was attacked by a British squadron, in the midst of the Spanish succession war. Targeted, the ship exploded after a shot touched its powder reserves. He sank quickly, taking with him nearly 600 crew men. And its estimated cargo at several tonnes of gold, silver and precious stones disappeared.
Since its sinking, San José has fueled the fantasies of generations of treasure researchers. Nicknamed “the Eldorado of the Seas”, its exact location remained unknown until the Colombian government announced in 2015 that it has located a suspicious wreck off its coast. This discovery had immediately aroused international reactions. In particular Spain, because it still claims the property of its former military ships.
For several years, for lack of concrete evidence, the identity of the ship remained questionable. But the objects observed on site, in particular the currencies, the cannons and the configuration of the site, suggested an origin compatible with the San José.
Coins struck in Lima as chronological proof of San José
To precisely document the objects present on the site, the researchers used a remote-controlled submarine vehicle, the Lynx Saab Seaeye. He was able to explore the wreckage almost 600 meters deep without damaging it. This robot has captured high definition images of the artefacts, including several dozen gold coins scattered around the stern of the ship. Thanks to photogrammetry, a 3D modeling technique by image, scientists were able to study every detail without taking out the objects from the water.
The documents analyzed are macuquinasSpanish colonial currencies carved by hand in gold ingots. Irregular, but rich in information, they display the columns of Hercules on the back above waves. This is a characteristic motif of Lima currency. On the obverse, there is a cross of Jerusalem framed by the coats of arms of the kingdoms of Castile and León. All in a typical style of the beginning of the 18th century.
© © Vargas Ariza, D., et al., 2025
Details of the part of 1707. © Vargas Ariza, D., et al., 2025
One of these parts has clear identifying elements. The letter “L” for Lima, the figure “8” designating its value in escudos, and the initial “H” of the Master Assayer (or tryer) Francisco de Hurtado. The latter, in monetary workshops, was to verify the purity and quality of precious metals. In addition, this piece is dated 1707. However, according to historians, the San José left Cartagena in 1708. This simple fact is enough to exclude any previous sinking. The concordance between the parts, the colonial registers and the historical dating therefore constituted a decisive argument to attribute the wreck to the San José.
Unprecedented archaeological cartography
Beyond the analysis of currencies, the researchers carried out a work of spatial documentation of unprecedented precision for this type of site. Using the underwater robot, they produced a complete map of the wreckage and its immediate environment. This operation, conducted in 2021 and 2022, made it possible to generate 3D digital models of the wreckage, incorporating georeferenced statements, speech therapomosaics and a digital model of seabed.
The study revealed three distinct areas of concentration of gold coins. They are located on a port and starboard section of the rear section of the galleon. These clusters of currencies are surrounded by period objects: dishes, everyday utensils, naval artillery, but also Chinese porcelain from the Kangxi dynasty (1662–1722). All this confirms the typical transoceanic exchanges of Spanish colonial trade. Cannons relating to 1665 have also been identified. They confirm that the ship had several decades of service at the time of the sinking several decades.
© © Vargas Ariza, D., et al., 2025
Three deposits of Macuquinas identified in Pupabine (B, C) and starboard (A). Objects from the edge and the cargo surrounds them. © Vargas Ariza, D., et al., 2025
This material organization on the site confirms the hypotheses on the origin of the treasure. The parts found would come from mining regions of Puno and Huamanga, in southern Peru, before being melted at Lima's currency. They were then transported to the port of Portobelo, on the Caribbean coast of Panama. Then they were embarked on the San José to Spain.
Lusts, diplomatic issues and methodological precautions
The probable identification of the San José galleon revives a complex legal and diplomatic conflict. Although archaeological data strengthen the allocation of the wreck to the ship flowed in 1708, the researchers remained cautious. The team recalls that other Spanish galleons could, in theory, correspond to this profile. This is why the project Hacia El Corazón del Galeón San Joséfunded by the Colombian ministries of culture and defense as well as by the Colombian Institute of Anthropology and History, continues a non -intrusive and rigorous approach, without recovery of objects at this stage.
But the implications exceed the scientific field. Spain claims the property of San José under the United Nations Convention on the Law of the Sea. It invokes the status of a warship. However, Colombia has not ratified this convention. It therefore considers the wreck as part of its national heritage, because of its location in its territorial waters.
This divergence blocks any potential restitution and complicates the management of the submerged treasury. Colombia wants to create a dedicated museum. But its legislation prohibits the sale of historical objects, even to finance research. For its part, Spain demands respect for international conventions. As Vargas Ariza note, this case illustrates the tensions between heritage protection, national sovereignty and economic interests linked to the exploitation of an exceptional archaeological site.
Source: Vargas Ariza, D., et al., (2025). “The Cobs in the Archaeological Context of the San José Galleon Shipwreck”. Antiquity, 1–6.
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