The document summarizes the Italian novel "I Promessi Sposi" ("The Betrothed") by Alessandro Manzoni. It describes how Manzoni was a former atheist who converted to Catholicism in 1810 and wrote "I Promessi Sposi" in 1821. The novel tells the story of Renzo and Lucia whose marriage is prevented by Don Rodrigo, but they are helped by the friar Fra Cristoforo and find refuge until after the plague they can finally marry.