Dom Carlos I of Portugal (English: Charles), known as the Diplomat (also known as the Martyr); Portuguese: o Diplomata and Portuguese: o Martirizado, was the King of Portugal and the Algarves. He was the first Portuguese king to be murdered since Sebastian of Portugal in 1578.
Carlos became king on 19 October 1889. After the 1890 British Ultimatum, a series of colonial treaties were signed with the United Kingdom of Great Britain and Ireland. One signed in August 1890 defined African colonial borders along the Zambezi and Congo rivers, whereas another signed on 14 October 1899 confirmed colonial treaties of the 17th century. These treaties stabilised the political balance in Africa, ending Portuguese claims of sovereignty on the Pink Map, a geographical conception of how Portuguese colonies would appear on a map if the territory between the coastal colonies of Angola and Mozambique could be connected with territory in central Africa. These central African territories were taken over by Great Britain, however, a concession that was viewed as humiliating in Portugal. The agreements were thus looked upon as unpopular in Portugal and were felt to be disadvantageous to the country.
On 1 February 1908, the royal family returned from the palace of Vila Viçosa to Lisbon. They travelled by train to Barreiro and, from there, they took a steamer to cross the Tagus River and disembarked at Cais do Sodré in central Lisbon. On their way to the royal palace, the open carriage with Carlos I and his family passed through the Terreiro do Paço fronting on the river. While crossing the square, shots were fired from the crowd by two republican activists: Alfredo Luís da Costa and Manuel Buiça.
Buiça, a former army sergeant and sharpshooter, fired five shots from a rifle hidden under his long overcoat. The king died immediately, his heir Luís Filipe was mortally wounded and Prince Manuel was hit in the arm. The queen alone escaped injury. The two assassins were killed on the spot by police and bodyguards; an innocent bystander was also killed in the confusion. The royal carriage turned into the nearby Navy Arsenal, where, about twenty minutes later, Prince Luís Filipe died. Several days later, the younger son, Prince Manuel, was proclaimed king of Portugal; he was the last of the Braganza-Saxe-Coburg and Gotha dynasty and the last king of Portugal as well.