António Eduardo Borges Coutinho de Medeiros was born in Lisbon on 3 May 1923, the second son of the third Marquis of Praia e Monforte.
He became a member of the Portuguese Democratic Movement in the National Assembly, for the district of Ponta Delgada, in 1969, along with Manuel Barbosa and João Silvestre Pacheco (obtaining 22.2% of the votes, the best results for an opposition, candidates).
Unsupported by the Military Governor of the Azores, General Altino Pinto de Magalhães, during negotiations with protesters, he was forced to publicly resign on the balcony of the Palace of Conceição.
[1] Following his stay in the Azores, he established his residence in São João do Estoril, maintaining links to regional and national politics.
The same acts of condolence for Jorge do Nascimento Cabral of the Social Democratic Party, who supported separatism for the Azores in the regional parliament the year earlier, was approved by majority.