The libretto was written by Francesco Maria Piave based on a Spanish drama, Don Álvaro o la fuerza del sino (1835), by Ángel de Saavedra, 3rd Duke of Rivas, with a scene adapted from Friedrich Schiller's Wallensteins Lager (Wallenstein's Camp).

In addition, the overture (to the revised version of the opera) is part of the standard repertoire for orchestras, often played as the opening piece at concerts.

After its premiere in Russia, La forza underwent some revisions and made its debut abroad with performances in Rome in 1863 under the title Don Alvaro.

Performances followed in Madrid (with the Duke of Rivas, the play's author, in attendance) and the opera subsequently travelled to New York, Vienna (1865), Buenos Aires (1866), and London (1867).

[citation needed] Following these productions, Verdi made further, more extensive revisions to the opera with additions to the libretto by Antonio Ghislanzoni.

[2] Critical editions[3] of all versions of the opera (including material from the original 1861 score) have been prepared by musicologist Philip Gossett of the University of Chicago.

Notwithstanding her tender regard for her father, who until now has always been kind to her, Leonora is ready to give up family and country in order to elope with Alvaro.

Aided by her confidante, Curra (Me pellegrina ed orfana – "Exiled and orphaned far from my childhood home"), she prepares to leave.

Leonora's brother Don Carlo di Vargas then enters, bent on avenging the family honor and the death of his father.

During the supper, Preziosilla, a pretty gypsy fortune teller, joins them and sings a song urging them to enlist in the army (Al suon del tamburo – "When side drums rattle") for Italy's freedom.

Carlo grills Trabuco about the identity of his traveling companion, but the company lets him know they don't like his prying questions.

After a somewhat surly reception by Fra Melitone, she tells the abbot, Padre Guardiano, her true name and her wish to spend the remainder of her life in the monastery's hermitage.

Padre Guardiano agrees to direct her to a secret cave in the mountains, where he alone will bring her food and where she will find a bell which she is to ring only in times of great danger or if she is on the point of death.

Leonora, Padre Guardiano, Fra Melitone, and the other monks join in prayer as she is formally accepted as tenant of the hermitage.

Scene 1: A forest near Velletri, in Italy Meanwhile, Alvaro, believing Leonora to be dead, has joined the Spanish army under the name of Don Federico Herreros and has distinguished himself for bravery (La vita è inferno all'infelice ... O tu che in seno agli angeli – "Life is a hell to an unhappy man."

As his wounded friend is taken away on the surgeon's stretcher, he opens the casket, finds his sister's portrait, and realizes Alvaro's true identity.

Trabucco, the peddler, tries to sell them his wares; Fra Melitone chastises them for their godless ways; and Preziosilla leads them in a chorus in praise of the military life (Rataplan, rataplan, della gloria – "Rum-tum-tum on the drum is the music that makes a soldier's martial spirit rise").

Carlo is mortally wounded by Alvaro, who invades the hermit's sanctuary to request the last offices for the dying man.

The Father Superior, who has come in answer to Leonora's alarm bell, orders Alvaro to stop cursing fate and to humble himself before God.

[14] The main theme in the musical scores for the films Jean de Florette and Manon des Sources (both 1986) was adapted by Jean-Claude Petit from the duet "Invano, Alvaro" in La forza del destino.