It deals with a variety of themes, from the cowardly, hypocritical nature of one prelate (Don Abbondio) and the heroic sainthood of other priests (Padre Cristoforo, Federico Borromeo), to the unwavering strength of love (the relationship between Renzo and Lucia, and their struggle to finally meet again and be married), and offers some keen insights into the meanderings of the human mind.
Manzoni hatched the basis for his novel in 1821 when he read a 1627 Italian edict that specified penalties for any priest who refused to perform a marriage when requested to do so. More material for his story came from Giuseppe Ripamonti's Milanese Chronicles.
The first version, Fermo e Lucia, was written between April 1821 and September 1823. He then heavily revised it, finishing in August 1825; it was published on 15 June 1827, after two years of corrections and proof-checking. Manzoni's chosen title, Gli sposi promessi, was changed for the sake of euphony shortly before its final commitment to printing.
In the early 19th century, there was still some controversy as to what form the standard literary language of Italy should take. Manzoni was firmly in favour of the dialect of Florence and, after "washing his vocabulary on the banks of the Arno" (as he put it), he revised the novel's language for its republication in 1842.