The novel deals with a variety of themes, for example: the illusory nature of political power and the inherent injustice of any legal system; the range of character among the Christian clergy from the cowardice of the parish priest Don Abbondio to the heroic sanctity of others (the friar Padre Cristoforo, the cardinal Federico Borromeo); and the unwavering strength of love (the relationship between Renzo and Lucia, and their struggle to finally meet again and be married).

Manzoni found 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.

Manzoni's chosen title, Gli sposi promessi, was changed for the sake of euphony shortly before its final commitment to printing.

It begins with Renzo and Lucia, a couple living in a village in Lombardy, near Lecco, on Lake Como, who are planning to wed on 8 November 1628.

When he presents himself for the wedding ceremony, Renzo is amazed to hear that the marriage is to be postponed (the priest didn't have the courage to tell the truth).

Lucia's mother, Agnese, advises Renzo to ask the advice of "Dr. Azzeccagarbugli" (Dr. Quibbleweaver, in Colquhoun's translation), a lawyer in the town of Lecco.

When Fra Cristoforo comes to Lucia's cottage and hears the story, he immediately goes to Don Rodrigo's mansion, where he finds the baron at a meal with his cousin Count Attilio, along with four guests, including the mayor and Dr. Azzeccagarbugli.

When Don Rodrigo is taken aside by the friar, he explodes with anger at his presumption and sends him away, but not before an old servant has a chance to offer his help to Cristoforo.

The fear of scandal, as well as manoeuvre, menaces, and manipulation from her father, induced Gertrude to lie to her interviewers in order to enter the convent of Monza, where she was received as la Signora.

Later, she fell under the spell of a young man of no scruples, Egidio, associated with the worst baron of that time, the Innominato (the "Unnamed").

He is saved in the nick of time by Ferrer, the Grand Chancellor, who arrives in a coach and announces he is taking the Commissioner to prison.

After witnessing these scenes, Renzo joins in a lively discussion and reveals views which attract the notice of a police agent in search of a scapegoat.

In the street Renzo announces loudly that he is being punished for his heroism the day before and, with the aid of sympathetic onlookers and political unrest brewing, he escapes.

Leaving the city by the same gate through which he entered, he sets off for Bergamo, knowing that his cousin Bortolo lives in a village nearby.

At an inn in Gorgonzola, he overhears a conversation which makes it clear to him how much trouble he is in and so he walks all night until he reaches the River Adda.

After a short sleep in a hut, he crosses the river at dawn in the boat of a fisherman and makes his way to his cousin's house, where he is welcomed as a silk-weaver under the pseudonym of Antonio Rivolta after he confesses everything to Bortolo.

Their reassurance is short-lived: when they receive no word from Fra Cristoforo for a long time, Agnese travels to Pescarenico, where she learns that he has been ordered by a superior to the town of Rimini.

The Unnamed is troubled by the sight of her, and spends a horrible night in which memories of his past and the uncertainty of his future almost drive him to suicide.

Meanwhile, Lucia spends a similarly restless night, during which she vows to renounce Renzo and maintain perpetual virginity if she is delivered from her predicament.

The astonishing course of events leads to an atmosphere in which Don Rodrigo can be defied openly and his fortunes take a turn for the worse.

Her life is not improved when a wealthy busybody, Donna Prassede, insists on taking her into her household and admonishing her for getting mixed up with a good-for-nothing like Renzo.

The last three dukes of the house of Gonzaga die without legitimate heirs sparking a war for control of northern Italy, with France and the Holy Roman Empire backing rival claimants.

In September 1629, German armies under Count Rambaldo di Collalto descend on Italy, looting and destroying.

These chapters are occupied with an account of the plague of 1630, largely based on Giuseppe Ripamonti's De peste quae fuit anno 1630 (published in 1640).

Manzoni's full version of this, Storia della Colonna Infame, was finished in 1829, but was not published until it was included as an appendix to the revised edition of 1842.

Grizo is then hit by karma when his greed to check for money in Don Roderigo's clothes makes him fall ill too, and dies quickly.

When they all return to their native village, Lucia and Renzo are finally married by Don Abbondio and the couple make a fresh start at a silk-mill at the gates of Bergamo.

Many expressions, quotes and names from the novel are still commonly used in Italian, such as Perpetua (meaning a priest's house worker) or Questo matrimonio non s'ha da fare ("This marriage is not to be performed", used ironically).

[14] A "modern opera" version, called The Betrothed Lovers, was written and produced by Michele Guardi with music by Pippo Flora, and first performed in 2010.

In May 2015, at a weekly general audience at St. Peter's Square, Pope Francis asked engaged couples to read the novel for edification before marriage.