Two years after declaring independence in 1822, Brazil's Emperor Dom Pedro I sanctioned the country's first constitution. Along with the executive, legislative, and judicial powers of government made commonplace by the Enlightenment, the Empire of Brazil's constitution established the moderating power, granting the Emperor of Brazil broad powers which resulted in frequent changes in government and brought the centralizing ambitions of the Brazilian monarchy into conflict with the interests of Brazil's provincial oligarchies, a conflict which led to Dom Pedro I’s abdication of the throne in 1831. Ruled by a regency from 1831 to 1840, Brazil’s territorial and political integrity suffered from a series of internal struggles collectively known as the Regency Rebellions (Revoltas Regenciais in Portuguese), among them the Ragamuffin War (Revoulção Farroupilha in Portuguese) from 1835 to 1845, the Balaiada (1838-1841), the Cabanagem (1835-1840), the Revolução Praieira (1848-1849), the Malê Revolt (1835) and the Sabinada (1837-1838). Externally, Brazil's ill-defined borders changed according to both diplomacy and conflicts such as the Argentine-Brazilian War (1825-1828) over the Empire of Brazil's Cisplatine Province in what is today Uruguay. With the over 50-year regency and reign of Dom Pedro II (1831-1889) came major changes in the Empire of Brazil, such as the rise of coffee as Brazil's top export, the gradual abolition of slavery and the increase in immigration, particularly from Europe and Asia. The devastating Paraguayan War (1865-1870) -- also known in Portuguese as the Guerra da Tríplice Aliança for the coalition Argentina, Brazil, and Uruguay formed to combat Paraguay -- gave rise to the Brazilian military's longstanding involvement in national politics, culminating in Field Marshal Deodoro da Fonseca's overthrow of Pedro II and the end of Brazil's monarchy in November 1889.

In the early 1820's, the United States seemed as much an ambition as a reality. Politically, the roles of the federal government and their relation to the states were the subject of great debate and conflict. Economically, the export-oriented system of slave labor in the South sat alongside a budding industrial economy in the North. From 1822 to 1889, the foreign policy of the United States crafted borders that continually pushed westward, until the country's dream of Manifest Destiny had come true and its territory stretched from the Atlantic to the Pacific oceans. While bargain or armed struggle provided the means of dealing with the country's immediate neighbors, the United States also devised policy programs for dealing with overseas foreign powers, most notably President James Monroe's statement in 1823, known as the Monroe Doctrine, that no part of the Americas should be "considered as subjects for future colonization by any European powers".

On May 26, 1824, President James Monroe, along with Secretary of State John Quincy Adams, officially received José Silvestre Rebello as Brazil's Chargé d'Affaires to the United States of America, initiating Brazil's longest-standing diplomatic relations. From that date until the end of the Brazilian Empire in 1889, interactions between the United States and Brazil revolved primarily around international trade and transport. Commercial relations between the two countries often resulted in cooperation, such as the signing in December 1828 of the Treaty of Amity, Commerce, and Navigation, or the establishment in 1865 of a steamship line between the two countries, serviced by the United States and Brazil Mail Steamship Company of New York. Subverting Britain's efforts to stamp out the slave trade also provided a point of collaboration. However, during times of war, such as the Argentine-Brazilian War, the American Civil War (1861-1865), and the Paraguayan War, each nation's obligations as neutrals clashed with their needs for international trade. Imprudent behavior by the United States' diplomatic representatives to Brazil, such as Condy Raguet and Henry A. Wise, could also strain relations between the two countries. Difficulties also arose in the 1850s regarding Brazil’s expansion into the Amazon river basin. For the majority of the period from 1822 to 1889, however, the role the United States played in Brazil's foreign relations paled in relation to that of Europe, particularly Britain, whose grip on Brazil's trade would only begin to loosen during the latter part of the Empire of Brazil.

Key events

• Argentine-Brazilian War, 1825-1828
• Paraguayan War, 1865-1870

Key figures

• Pedro II, Emperor of Brazil, 1825-1891
• Rebello, José Silvestre, -1844

Key subjects

• Brazil--Politics and government--1822-1889
• Monroe doctrine