History of the Ship

Nuestra Señora de las Mercedes sailed for over 15 years from 1788 until 1804 when it sunk in a battle with the British Navy. It traveled across the Atlantic Ocean between Spanish viceroyalties in South and Central America, and on the shores around Spain itself. In a period of conflict between Spain, France, and England, Nuestra Señora de las Mercedes began as an attempt to protect Spain from military engagement but ended with a declaration of war against Britain. Today, the discovery of its remains by private company OMEX in 2007 led to a court case that is crucial to understanding how maritime history is understood in law.1

What type of ship was Nuestra Señora de las Mercedes?

Watercolor painting of a 1790s French frigate Prudente by François Roux (1850).

Nuestra Señora de las Mercedes was a 38-gun frigate built in the port of Havana, Cuba. At this time, frigates were examples of warships that featured technological innovation that maximized their speed and fighting power; they typically featured at least one gundeck that could hold anywhere between 30-44 cannons. While being useful in direct naval conflicts, they were also utilized to carry out missions such as transporting money, soldiers, and people of power. 2

French Revolutionary & Napoleonic Wars

The French Revolutionary Wars (1792-1802) were fought by coalitions of European powers against a Revolutionary France that threatened monarchies in other European countries. In the first coalition, Spain was allied with Britain, Austria, Prussia, and other countries against France.3 In 1796, however, Spain’s growing concerns about the threat of French expansionism and invasion led to the Treaty of Il Defonso where they pledged their support for France. The Treaty of Amiens of 1802 was a brief respite between fighting European powers, but fighting soon resumed between France and Britain in 1803.

Knowing the outright supply of military forces to France would anger Britain, a secret agreement was made to provide financial support to France instead as Spain sought to appease them. It was these circumstances that led to the dispatch of frigates to return with wealth from Spain’s viceroyalties in the Americas. Arriving in the viceroyalty of what is now Peru in August 1803, the port supplied them Hundreds of thousands of silver pesos, also known as specie, were loaded onto the ship in the port of El Callao. The ship then sailed to Montevideo and began its journey across the Atlantic with three other Spanish royal navy frigates.4

The Battle of Cape St. Mary

Sir Graham Moore’s Action Off Cape St. Mary by Thomas Sutherland, 1820

British naval forces had received reports of a Spanish navy squadron approaching Spain leading to an immediate dispatch of British ships to intercept them off the coast of Portugal led by Captain Graham Moore above the Indefatigable. On the morning of October 5, 1804, the British squadron sighted and gave chase to the Spanish frigates. Upon reaching them, Captain Graham Moore gave a warning shot but upon no response, firing commenced. In minutes, the Mercedes violently exploded and within the hour the three remaining Spanish frigates were captured and impounded by the British squadron. All aboard the Mercedes perished, except for forty who were pulled aboard the British Amphion.5

As soon as the [British] officer returned with an unsatisfactory answer, I fired another shot a-head of the Admiral, and bore down close on his weather-bow. At this moment the Admiral’s second a-stern fired into the Amphion; the Admiral fired in to the Indefatigable; and I made the signal for close battle, which was instantly commenced with all the alacrity and vigour of English sailors. In less than ten minutes, la Mercedes, the Admiral’s second a-stern, blew up along-side the Amphion, with a tremendous explosion.

Captain Graham Moore, Indefatigable6

The news of the sinking of Nuestra Señora de las Mercedes quickly reached Spain. Spanish diplomats pressed arguments that Britain was at fault for attacking a neutral power, to which Britain responded the specie carried by the Mercedes was destined for their enemy, France. Soon after, however, any hope of neutrality ended as Spain declared war on Britain on December 14, 1804. 7

Footnote Citations
  1. Delgado, James P., and Goold, James A. “Background to the ‘Black Swan’ Case: The Identification as Nuestra Señora de las Mercedes”. International Journal of Nautical Archaeology, Vol. 50. Issue 2 (April 2022), under “Legal Background” & “Historical Background”.
  2. Delgado and Goold, “Background to the ‘Black Swan’ Case…”.
  3. Harrison W. Mark, “French Revolutionary Wars”, World History Encyclopedia, August 25 2023. https://www.worldhistory.org/French_Revolutionary_Wars/.
  4. Oddysey Marine v. Unidentified Shipwrecked Vessel, 675 F.Supp.2d 1126 (2009), 4
  5. Delgado and Goold, “Background to the ‘Black Swan’ Case…”.
  6. Oddysey Marine v. Unidentified Shipwrecked Vessel, 675 F.Supp.2d 1126 (2009), 4.
  7. Oddysey Marine v. Unidentified Shipwrecked Vessel, 675 F.Supp.2d 1126 (2009), 4.