The interior of the Amazon basin has had an interesting history. While Manaus, the largest city in the interior of the Amazon, was founded in the 1660s, the western Amazon was one of the last areas of South America to be explored and settled by Europeans and was still sparsely settled by the collapse of the Spanish Empire in the 1820s. Because of this, the borders between the South American countries remained largely in flux throughout the 19th century and disputes were common. Ecuador claimed an area of what is now Peru roughly equal to its current territory, extending east to the Amazon River what is now Iquitos. In order for Colombia to stake a claim to a portion of the Amazon, the city of Leticia was founded on the river in 1867 at what is now Colombia’s southernmost point. Peru disputed this claim for half a century until 1922 when they recognized Colombia’s claim in exchange for Colombia supporting Peru in their dispute with Ecuador. Further south, Bolivia and Brazil were continually disputing the territory of what is now the Brazilian state of Acre.
Acre had been largely ignored by Europeans and South American governments until the latter half of the 19th century. Due to its geography east of the Andes Mountains but near the western headwaters of the Amazon River, it was a difficult region to get to. Additionally, its lack of gold, silver, or other valuable natural resources led to the area being ignored in favor of areas like Potosi in Bolivia and Minas Gerais in Brazil that held vast mineral wealth. As such, when the South American countries gained independence in the 1820s and 1830s, the question of who owned Acre was not a priority. While the few European settlements in the area were Portuguese and Brazilian, Acre became part of Bolivia when it gained its independence.
The Industrial Revolution changed Acre’s fortunes, however, with the increased use of natural rubber and latex in industrial processes. The expanded use of rubber sparked a rubber boom throughout the Amazon basin. As Brazilians moved into the interior of the country, more Brazilians flocked to Acre. However, the area was still part of Bolivia, and had been reaffirmed as such in the 1867 Treaty of Ayacucho between Bolivia and Brazil. As Bolivia tried to move in to enforce control of the Acre region and the rubber plantations there, the Brazilian population in Acre and the state government of neighboring Amazonas attempted to claim Acre for Brazil. In 1899, Luis Gálvez Rodriguez de Arias, a Spanish journalist in Manaus, entered Acre on an expedition funded by the government of Amazonas. Gálvez launched a rebellion in Acre with a force made up of veterans of the war in Cuba as well as local plantation workers. On July 14, 1899, Gálvez declared the Republic of Acre independent with himself as president. The Bolivian government sent a small force into Acre that was repulsed, and the First Republic of Acre lasted for eight months. Gálvez’s republic only ended when Brazil, mindful of and wanting to respect the Treaty of Ayacucho, suppressed the Acre rebellion in March of 1900 to restore the territory to Bolivia.
Although Gálvez was defeated and sent back to his native Spain, the pro-Brazilian sentiment only grew in Acre. Another attempt at secession in November of 1900 established the brief Second Republic of Acre, but was again suppressed and the territory returned to Bolivia. In 1903, the leaders of Acre’s Brazilian population again rebelled against the Bolivian government. This time, the rebellion was led by José Plácido de Castro, a surveyor who had been working in Acre since 1899. Plácido de Castro took command of the Acrean army and defeated the Bolivian forces in the region in a number of engagements. He declared the Third Republic of Acre in January 1903. Brazil again got involved, however this time with diplomatic intervention. Brazil’s foreign minister, the Baron of Rio Branco, proposed a treaty by which Brazil would purchase Acre from Bolivia for two million British pounds. The resulting treaty, the Treaty of Petropolis, also settled other territorial disputes between Brazil and Bolivia. Bolivia gained control over land south of the Abunâ River, which remains part of the border between the two countries today. The Treaty of Petropolis also had Brazil commit to building a railway between the Bolivian city of Riberalta and the Brazilian city of Porto Velho to easier facilitate trade from northern Bolivia.
After the annexation of Acre into Brazil, president Francisco Rodrigues Alves named it a territory of Brazil in 1904. Plácido de Castro was named the first governor of the Territory of Acre in 1906, and the region continued to prosper as the rubber boom spurred population and economic growth throughout northwest Brazil. Acre was elevated from a territory to a state in 1962.