Marshal Deodoro was born in the city of Alagoas, Alagoas, on August 5, 1827 and studied at a military school since he was 16 years old. In 1848, at the age of 21, he joined the troops heading to Pernambuco to fight the Praieira Revolution and actively participated in other conflicts during the Empire, such as the expeditionary brigade to the La Plata River, the siege of Montevideo and the Paraguayan War.
He officially entered politics in 1885, when he held the position of president (equivalent to the current governor) of the province of Rio Grande do Sul. He assumed the presidency of the Military Club from 1887 to 1889 and headed the army's anti-slavery sector. With the title of marshal, Deodoro da Fonseca proclaimed the Brazilian republic on November 15, 1889 and assumed the leadership of the provisional government.
The first republican constitution established that elections in Brazil would be direct and that the president and his deputy would be elected by popular vote. However, it also determined that, exceptionally, the first president and first deputy would be elected indirectly, that is, by the National Congress. That is what happened. The day after the promulgation of the Constitution, Congress indirectly elected Marshals Deodoro da Fonseca as president and Floriano Peixoto as vice president on February 25, 1891.
The Marshal's government was due to end in 1894, but the period saw serious political and economic problems. The economic policy, which had as Minister of Finance Rui Barbosa, was marked by "encilamento", which was characterized by the encouragement of the issuance of currency by some banks and the creation of corporations. As a result, there was strong financial speculation and bankruptcy of banks and companies.
The formation of a new ministry led by Baron Lucena, a politician linked to the monarchical order, the attempt to centralize power and the resistance encountered in the military led the country to a political crisis, which had its apex in the dissolution of the National Congress. At the same time the influence of Floriano Peixoto was growing in the military milieu, which also opposed Deodoro along with the legalistic forces that led to the resignation of Deodoro da Fonseca on November 23, 1891.