This small canvas - actually a painting on paper glued onto canvas, a technique often used in the romantic period due to its coupling of the smoothness of paper with the durability of canvas - is one of the few paintings executed by Jean Baptiste Debret during his stay of more than fifteen years in Brazil. Probably painted a few months after artist's arrival in Rio de Janeiro in March 1816, this scene depicts a historical event when the Portuguese government, then headquartered in the city of Rio de Janeiro, decided to send a division of the Army to the south of Brazil to deal with the controversy in the Río de La Plata region. King Dom João VI had decided to annex the Eastern Band - present-day Uruguay - to the king-dom of Brazil and involved the empire in conflicts that extended up to the War of the Triple Alliance, wich took place between 1864 and 1870. Dom João sent the troops because his wife, Carlota Joaquina, as a member of the reigning Spanish House of Bourboun, had a right to the Spanish territories in America, since Spain was under the rule of Napoleon Bonaparte. The forces sent consisted of 4,813 men. The group was stationed for some time at Armação (later named Praia Grande, in Niterói) and left in two phases, the first in January 1816, and the second in June of that same year. Debret described the episode in his book Voyage pittoresque et historique au Brésil: "The Portuguese government's decision to take possession of Montevideo, in order to make this territory the border of Brazil with the Spanish possessions, was carried out in 1816 [...] Following the military exercises held daily in the regent's presence, for his diversion, the supreme commander of the Portuguese troops Marshall Beresford organized a last review, with a small simulated war, at this picturesque site that presented various positions for attack and defense".