In 1899–1900, the Spanish journalist and former diplomat Luis Gálvez Rodríguez de Arias led an expedition that sought to seize control of what is now Acre from Bolivia.

The expedition was secretly financed by the Amazonas state government and aimed to incorporate Acre into Brazil after its independence from Bolivia.

The first republic lasted until March 1900, when the Brazilian government sent troops to arrest Gálvez and restore Acre to Bolivia.

After the failure of the second attempt of Acre to secede from Bolivia, a veteran soldier from Rio Grande do Sul who had fought in the Federalist Revolution of 1893, José Plácido de Castro, was approached by the separatist Acre leaders and offered the opportunity to lead the independence movement against Bolivia.

Castro, who had been working in Acre since 1899 as a chief surveyor of an expedition and was about to go back to Rio de Janeiro, accepted the offer.