Manuel Marques de Sousa, Count of Porto Alegre, nicknamed "the Gloved Centaur", was an army officer, politician and abolitionist of the Empire of Brazil. Born into a wealthy family of military background, Manuel Marques de Sousa joined the Portuguese Army in Brazil in 1817 when he was little more than a child. His military initiation occurred in the conquest of the Banda Oriental, which was annexed and became the southernmost Brazilian province of Cisplatina in 1821. For most of the 1820s, he was embroiled in the Brazilian effort to keep Cisplatina as part of its territory: first during the struggle for Brazilian independence and then in the Cisplatine War. It would ultimately prove a futile attempt, as Cisplatina successfully separated from Brazil to become the independent nation of Uruguay in 1828.

The Empire of Brazil was a 19th-century state that broadly comprised the territories which form modern Brazil and Uruguay until the latter achieved independence in 1828. Its government was a representative parliamentary constitutional monarchy under the rule of Emperors Pedro I and his son Pedro II. A colony of the Kingdom of Portugal, Brazil became the seat of the Portuguese Empire in 1808, when the Portuguese Prince regent, later King Dom John VI, fled from Napoleon's invasion of Portugal and established himself and his government in the Brazilian city of Rio de Janeiro. John VI later returned to Portugal, leaving his eldest son and heir-apparent, Pedro, to rule the Kingdom of Brazil as regent. On 7 September 1822, Pedro declared the independence of Brazil and, after waging a successful war against his father's kingdom, was acclaimed on 12 October as Pedro I, the first Emperor of Brazil. The new country was huge, sparsely populated, and ethnically diverse.