The immediate cause of the revolt was the
1890 British Ultimatum, also known as Lord Salisbury's Ultimatum, which was delivered to Portugal on 11 January 1890. Portugal had attempted to claim a large area of land in southern Africa between its colonies of
Mozambique and
Angola, which had been included in Portugal's
Pink Map prepared in 1885 to show the country's sovereignty over that land. The Ultimatum demanded the withdrawal of Portuguese forces from areas claimed by Portugal based on Portuguese exploration, as Britain claimed these on the basis of possession. The seeming ease by which the Portuguese government gave in to British demands was seen as a national humiliation by most people in Portugal, including republican opponents of the monarchy who saw the Portuguese response as evidence of the monarchy's weakness. On 1 January 1891, the
Portuguese Republican Party met, from which an elected committee emerged, consisting of
Teófilo Braga,
Manuel de Arriaga,
Francisco Manuel Homem Cristo,
José Jacinto Nunes,
José Francisco de Azevedo e Silva,
Bernardino Pereira Pinheiro and
Sebastião de Magalhães Lima. These presented a long-term political action plan, which believed that, given time, a Republic would inevitably evolve. However, their leadership was not recognized by all republicans as some were calling for immediate action. These, in addition to being outraged by the outcome of the Ultimatum and seeing it as a justification for overthrowing the monarchy, were inspired by the proclamation of a Republic in the former Portuguese colony of
Brazil, on 15 November 1889. Support for the Republican cause was particularly strong in Porto. The leading figures in the revolt among the military were mainly sergeants and soldiers and it became known as the “revolt of the sergeants”. They lacked the support of any high-ranking officer. They were led by Captain
António Amaral Leitão. As well, a number of civilians were involved including the lawyer and politician,
Augusto Alves da Veiga, the actor
Miguel Verdial, the journalist
João Chagas, the photographer and film director,
Aurélio da Paz dos Reis, and the writer and philosopher,
Sampaio Bruno. ==The event==