A Spanish frigate blew up in 1804 with Captain Alvear's wife and seven children aboard, and in 2007 his descendants sued for its silver

The Spanish Navy frigate Nuestra Señora de las Mercedes left Lima on 31 March 1804 carrying about 900,000 silver pesos, 5,809 gold pesos and almost 2,000 copper and tin ingots. Captain Diego de Alvear was sailing home on her with his family. At Montevideo he was moved to the frigate Medea to replace a sick officer. His wife, four daughters, three sons and a nephew stayed on the Mercedes. His son Carlos María went with him. On 5 October 1804, one day from Cádiz, four British frigates stopped the squadron. Minutes into the fight the Mercedes exploded. Alvear wrote that she "jumped through the air". Except for fifty sailors, everyone aboard died, including his family. In 2007 Odyssey Marine Exploration recovered about 595,000 coins from a wreck west of Gibraltar and claimed them in a Florida federal court. Spain said the wreck was its warship. Peru claimed as a successor state to Spain. Twenty-five individuals, among them Santiago and Emilio de Alvear, claimed as descendants of people with cargo aboard. On 21 September 2011 the Eleventh Circuit held that the cargo shared the warship's immunity. Odyssey returned the coins to Spain on 25 February 2012, and the Supreme Court declined the case on 14 May 2012. On 2 December 2012, 14.5 tons of the coins went into the National Museum of Underwater Archaeology in Cartagena. The descendants received nothing.