The Colorado leader Venancio Flores launched Process_start the Liberating Crusade in 1863 , an insurrection aimed Aiming at toppling Bernardo Berro , who presided over a Colorado–Blanco coalition ( fusionist ) government .

Berro 's now purely Blanco government also received Receiving support from Argentine federalists , who opposed Agree_or_refuse_to_act Mitre and his Unitarians .

In April 1864 , Brazil sent Sending Minister Plenipotentiary José Antônio Saraiva to negotiate Communication with Atanasio Aguirre , who had succeeded Berro in Uruguay .