In November 1904, the city of Rio de Janeiro was shaken by the Vaccine Revolt, a reaction to mandatory smallpox immunization. The fights and riots that took over the streets were the trigger for the outbreak of a revolt that had been in rehearsal at the Clube Militar. The military officers, dissatisfied with the government of Rodrigues Alves, a civilian representative of the coffee oligarchy, were plotting a coup against the president.
Escola Militar da Praia Vermelha. "The Military School of Brazil" - 1905 - Leon de Rennes. Fundação Biblioteca Nacional
The movement's leaders allied themselves with students from the Escola Militar da Praia Vermelha. Founded in 1857, the institution trained civil and military engineers, bringing together students and professors who had been active in the Brazilian political scene since the days of the Empire. Senator Lauro Sodré, a former student and staunch opponent of the mandatory vaccination law, led the roughly 300 rebels.
On November 14th, the climate of insurgency in Rio de Janeiro reached its peak, forming the ideal setting for the outbreak of the coup attempt. Setting out from the school toward the Palácio do Catete, the soldiers were making their way along Rua da Passagem when they encountered the Police Brigade, whose troops were far more numerous and stood in defense of the government. The two groups marched almost blindly, since the lampposts that lit the streets had been smashed during the demonstrations of the previous days.
O Paiz newspaper, Rio de Janeiro, no. 7343, p. 1, Nov. 15, 1904. National Library Newspaper Archive
Amid almost complete darkness, as gunfire burst out on all sides, the two groups retreated. Dozens of dead and wounded were counted in both troops. The loyalist forces emerged victorious after bombarding the Military School with warships during the early hours of the morning. The revolt led to the closing of the officer training center and the expulsion of the military personnel involved from the Army.