Deodoro da Fonseca Marshal Manuel Deodoro da Fonseca ( ; 5 August 1827 – 23 August 1892 ) became the first president of the Republic of Brazil after heading a military coup that deposed Emperor Pedro II and proclaimed the Republic in 1889 , dis - establishing the Empire of Brazil . Biography . Fonseca was born the third child of a large military family in Vila Madalena , Alagoas , a town that today bears his name as Marechal Deodoro , in Northeast Brazil . He was the son of Manuel Mendes da Fonseca Galvão ( 1785 - 1859 ) and his wife Rosa Maria Paulina de Barros Cavalcanti ( 1802 - 1873 ) . In the period of the Brazilian Empire , his older brother Severino Martins da Fonseca was created the first Baron of Alagoas . Another notable relative was the Portuguese humanist Francisco de Holanda ( d . 1585 ) , his remote uncle . Fonseca pursued a military career that was notable for his suppression of the Praieira revolt in Pernambuco in 1848 , Brazil ' s response to the European year of failed liberal revolutions . He also saw action during the Paraguayan War ( 1864 – 1870 ) , attaining the rank of captain . In 1884 he was promoted to the rank of field - marshal , and he later achieved the rank of full marshal . His personal courage , military competence and manly personal style made him a national figure . As Governor of Rio Grande do Sul , Fonseca was courted by republican intellectuals such as Benjamin Constant and Rui Barbosa in the café society of São Paulo . In 1886 , alerted that the imperial government was ordering the arrest of prominent republicans , Fonseca went to Rio de Janeiro and assumed leadership of the army faction that was favorable to the abolition of slavery . Emperor Pedro II had advocated the abolition of slavery for decades , freeing his own slaves in 1840 , but he believed slavery should be done away with slowly , so as not to damage the Brazilian economy . His daughter , Isabel , Princess Imperial of Brazil , abolished slavery entirely in 1888 , during her third regency ( while her father was away from the country ) . Enraged oligarchs played a role in the subsequent coup d ' état . Fonseca ' s prestige placed him at the head of the military coup that deposed the emperor on 15 November 1889 , and he was briefly the head of the provisional government that called a Constituent Congress to draft a new constitution for a United States of Brazil . Soon , however , he was in conflict with the civilian republican leaders . His election as president on 26 February 1891 , by a narrow plurality , was backed with military pressure on Congress . The Fonseca administration , divided by political and personal animosity between the president and Vice - President Floriano Peixoto , encountered strong opposition within the Congress , which chose a policy of obstruction . During the first months of his presidency , he permitted his ministers almost unrestricted control of their ministries . Arbitrary presidential decrees ( such as the concession of the port of Torres to a private company ) and the disastrous conduct of economic policy during the bubble of the Encilhamento strengthened the resistance in Congress , which coalesced round Vice - President Peixoto , and soured public opinion . This also caused republicans of the South to withdraw their support from the marshal and provisional government . The situation reached a crisis stage when Fonseca dissolved the National Congress and declared a " state of emergency " on 3 November 1891 . A group of deputies opposed this decision and found support among the high - ranking officers of the Navy , including Admiral Custódio José de Melo . The marshal found himself on the brink of a civil war . On 23 November 1891 he signed a resignation ( to no one in particular ) and turned over the presidency to Floriano Peixoto . Deodoro da Fonseca died in Rio de Janeiro on 23 August 1892 .