History of Portugal (1834–1910)
Militant Republicans and their allies in the Carbonária were not willing to remain in the shadows of the constitutional monarchy. Between 4–5 October 1910, members of the Carbonária, republican youth, and elements of the army instigated a coup d'état against the already weak constitutional monarchy. The young king and his family, after a few miscues, escaped from the Palace in Mafra to exile in England. On the morning of 5 October 1910, the Republic was declared from the balcony of Lisbon City Hall, ending eight centuries of monarchy in Portugal.
Duarte Nuno, Duke of Braganza
After the death of his uncle Afonso in 1920, ex-King Manuel II had no close relatives who could claim the throne according to the Constitutional Charter of 1826 (the constitution in force from 1842 until the overthrow of the monarchy in 1910). The conflict between the Miguelist line and the Braganza-Saxe-Coburg and Gotha's was not just about which person should be sovereign; it was also about how much power the sovereign should have. The Miguelists upheld Portugal's tradition of autocratic absolutism, while the Braganza-Saxe-Coburg and Gotha's adhered to constitutional monarchy.