Diego de Alvear y Ponce de León

After entering the Spanish navy as midshipman (1770), he arrived at the Rio de la Plata in 1774 and fought in the "Sacramento War" (also known as "Ceballos Expedition" 1776-1777).

[2] Its name derives from a colonial conflict between Spain and Portugal for control of Colonia del Sacramento[3] in what today is Uruguay, where the Spanish forces were commanded by Pedro de Cevallos.

[6] On August 7, 1804 Diego de Alvear, already a general, embarked in Montevideo en route to Spain in the frigate "Mercedes" carrying with him the riches accumulated after those many years of service in the River Plate area, and also his wife and children.

The encounter soon turned into a battle, and a Royal Navy carronade soon hit the "Mercedes", which sank, carrying with her Don Diego's riches and the life of his wife and children.

Diego de Alvear organized the city's defenses, having been one of his first successes to get the French Rosilly flotilla, interned in Cádiz Bay until then (as until a month and a half before France had been an ally) surrender in June 1808.

Diego de Alvear was opposed to this and organized a volunteer militia in Montilla, resisting the absolutist rebels until the arrival of reinforcements which ended the movement.

Don Diego spoke several languages: Spanish, Latin, English, French, Italian, Portuguese and some Tupí and Guaraní, having learned these two latter ones during his geographic work in the colonial sector he commanded.

He also had great mathematical and astronomical knowledge, connected with his military activities in the navy and army artillery and the work he did delimiting the colonial possession borders between Spain and Portugal in the River Plate area.

The wreck of the frigate Mercedes, whose sinking caused the death of Alvear's first wife and his children, was recently found and salvaged by the treasure hunter company Odyssey Marine Exploration between March and May 2007.