Narcís Monturiol (1819–1885) played an essential role in the history of submarine navigation. He was a person of strong convictions and fought for democracy at a time of changes and political convulsions in the Spanish society. Utopian republican and socialist, he spread the Communist ideas of Étienne Cabet in Catalonia, organizing the Cabetians around the weekly, La Fraternidad (1847–1848). He also became the leader of the Icarian community in Barcelona. Frequently persecuted because of his political beliefs, he was often forced to seek refuge in Cadaqués, and it was there that he conceived his project of a submarine vessel, the Ictineu. Although treated with mistrust by the authorities, he was able to secure sufficient financial and technical support to carry out the project. Together with a team of technicians, he constructed the first Ictineu, which was launched in the waters of Barcelona in 1859, Subsequent improvements led to a second Ictineu, launched in 1864 and fitted in 1867 with a steam engine. However, economic difficulties led to eventual failure. As an autodidact, Monturiol received the support of Barcelona’s scientific elite and continued inventing until his death. His work, Ensayo sobre el arte de navegar por debajo del agua (Essay on the Art of Navigating Under Water), was a pioneering, monumental work about submarine navigation and a remarkable contribution to the historiography of science and technology.