In 1869, de Quental founded the newspaper, "A República - Jornal da Democracia Portuguesa" with Oliveira Martins, and in 1872, along with José Fontana, began to edit the magazine "O Pensamento Social". In 1871, the year of the Paris Commune, de Quental organized the famous "Conferências do Casino" (), which marked the beginning of the spread of Socialist and Anarchist ideas in Portugal; in this de Quental distinguished himself as a crusader for republican ideals. He presented himself on two occasions (1879 and 1881) as a candidate for the Partido Socialista Português (Portuguese Socialist Party).