Set in Biscay in Aragon, at the beginning of the XV Century
ACT ONE
The Duel
Scene I
The Royal Palace of Aliaferia in Biscay
In Biscay in the royal palace the courtiers are awaiting the return of their lord - the Count de Luna. The Count is in love with Leonora, a young lady-in-waiting to the Queen, and as he is afraid she will yield to the advances of his hated rival, a troubadour - Il Trovatore, he spends the best part of the night keeping watch on her residence. Ferrando, the captain of the guard, tells the grim tale of an old gypsy woman who was condemned to death for witchcraft and burnt at the stake, and of her daughter Azucena who had avenged her mother's death by abducting one of the two sons of the old Conte di Luna and flinging him on to the same bonfire. The old count died of a broken heart. It is a blood-curdling story and the bystanders call down curses on the evil witch. It is believed that the old gypsy's ghost still haunts the palace and grisly stories are told of her doings. At the sudden striking of the midnight bell, the thoroughly frightened servants disperse in terror.
Scene II
In the gardens of the Royal Palace
Whilst strolling in the gardens of the palace of Aliaferia by night, Leonora reveals to her confidante Inez her love for Manrico, the troubadour, and the unknown cavalier, victor of many tournaments and the singer of enchanting songs in the night. As Leonora and Inez retire to their rooms, the Count de Luna arrives. Seeing the light from Leonora's balcony, he approaches, intent on paying her a visit; but he is suddenly frozen by the distant sound of a lute - it is the troubadour singing to Leonora! Consumed by jealousy the Count tries to draw his beloved into a trap, conceals himself in his cloak and waits. When Leonora comes down, having been allured by the music, she mistakes him for the troubadour and throws herself into his arms to proclaim her undying love. Il Trovatore observes the embrace and is dumbfounded. Angrily he accuses Leonora of deceiving him. The misunderstanding is soon cleared up. Leonora, recognizing him, and her error, throws herself at the troubadour's feet, and swears her love and loyalty. The Count de Luna is furious with jealousy and forces his rival to reveal his identity. When he recognises the troubadour as being Manrico, a follower of the rebel Urgel, he challenges him to a duel. The two of them draw their swords while Leonora falls senseless to the ground. The Count is wounded in the duel but his rival spares his life.
ACT TWO
The Gypsy
Scene I
A gypsy camp on the mountains of Biscay
In a gypsy camp in the mountains of Biscay, Manrico is with Azucena whom he believes to be his mother. She tells him how her mother was accused by a haughty Count of having bewitched his young son; how she was brought in chains to meet her doom at this very spot; how she herself followed, her own baby in her arms, weeping; how her mother was viciously thrust upon the stake. Her mother's last words were "Avenge me! Those words have ever since echoed in her heart. Manrico asks if she was avenged. Azucena replies that she abducted the Count's son and brought him here, where the fire still burned. Despite the baby's crying and her heart-breaking maternal feelings, a horrible vision appeared of the killers and her mother and blindly she seized the baby in her trembling hands and thrust it on the fire. In an instant the vision was gone. Only the raging flames remained; and there beside her was the son of the wicked Count. It was her own son she had cast into the fire! She shudders and Manrico is horror-struck. Suddenly the thought strikes him; who is he, he wonders, if he is not her son? Why did some mysterious force stay his hand in the duel with the Conte di Luna? Azucena assures him that he is indeed her son, that the recollection of that awful event has brought foolish words to her lips. Azucena tries to distract his attention from such thoughts and implores him to kill the count if ever they should fight again. Manrico swears to do so. A messenger brings urgent news to Manrico that Leonora believes him dead, and is consequently about to join the convent in order to avoid the attentions of the Count. In spite of Azucena's efforts to dissuade him, the troubadour decides to leave and seek out Leonora to prevent her from taking the vows.
Scene II
The Convent beside the fortress of Castellor
The Conte di Luna also learns of Leonora's decision and, convinced that his rival is dead, goes to the convent with some followers to block Leonora's path and abduct her. Leonora is approaching the convent, trying to console the other ladies-in-waiting, who are upset about her decision to take the religious vows. Manrico, however, arrives unexpectedly, followed shortly afterwards by some of Urgel's rebels. In the fierce fight that ensues between the two rival groups, the Count and his men are disarmed and the Troubadour escapes with his beloved.
ACT THREE
The Gypsy's Son
Scene I
The Camp of the Royal Troops beside the Fortress of Castellor
The royal troops under the command of the Count de Luna, encamped beneath the stronghold of Castellor, which has been captured by Urgel's guards, are waiting to launch an attack. Ferrando gives the news that a gypsy woman has been apprehended as a possible spy and taken before the court. It is Azucena. She declares she has come from Biscay in search of the son who has abandoned her but Ferrando recognises her as the kidnapper of the child. Desperately she cries out for her son, Manrico, to come to her aid. Recognizing in her now the mother of his enemy and his hated rival, as well as the killer of his brother, the Count exults in the punishment he will wreak on her. He gives orders for her to be taken away and burnt at the stake.
Scene II
Entrance Hall in the Chapel of Castellor
At Castellor Leonora and Manrico are approaching the altar about to exchange their marital vows. The bride-to-be is worried about the attack of the king's army but 'Il Trovatore' comforts her by assuring her that as soon as he is her husband, he will feel stronger and will therefore fight with greater courage. Suddenly Ruiz arrives, out of breath to bring an urgent message - Azucena is going to be burnt at the stake. Manrico reveals to Leonora that the gypsy is, in fact, his mother and rushes off to rescue her.
ACT FOUR
Torture
Scene I
The Royal Palace in Biscay
Manrico is captured and imprisoned and has been condemned to death. From the tower of the Aliaferia Palace, death bells can be heard and the 'Miserere' for the condemned. Leonora listens to the final goodbye from her lover. To save his life she agrees to marry the Count. The offer is accepted. Leonora herself wants to take the news to the prisoner and permission is granted, but she secretly takes some poison concealed in her ring.
Scene II
The Prison Tower in the Royal Palace in Biscay
Manrico seeks to comfort his mother who is tormented by the thought that she will be burnt to death. Unexpectedly Leonora enters and throws herself into the troubadour's arms, telling him that he has been pardoned and urging him to flee. At first he is overjoyed but then, when he realises the high price of the pardon he becomes angry with Leonora and disdains to accept clemency. But the poison takes effect instantly. Leonora dies and Manrico is overcome with grief and remorse. The Conte di Luna, having ascertained that Leonora deceived him and died for her true love, condemns Manrico to death and forces Azucena to witness his agony from the prison window. When he has been executed, the gypsy, almost beside herself, cries out to the horrified Count: "He was your brother"! "Mother you are avenged!".
The opera which proved that Verdi had reached his full artistic maturity 
Il Trovatore is one of the three great operas (along with Rigoletto and La Traviata) with which Giuseppe Verdi reached his full artistic maturity and was recognized as the greatest Italian composer of the 1800s. After the success of Rigoletto at Teatro La Fenice in Venice in March 1851, Verdi returned to Busseto, his home town, where he lived with the soprano Giuseppina Strepponi. Their living together out of matrimony was considered scandalous in the small town.
His next piece of work had already started to take shape in January of that year, when the Maestro had recommended to the librettist Salvatore Cammarano to buy a copy of El Trovador by the Spanish writer Antonio Garcìa-Gutiérrez. It was a story from the romantic period, set in Madrid in 1836, which had been very successful and had made a great impression on the public, above all for the power and originality of the plot and of the characters. Verdi himself loved these qualities and made an agreement with Cammarano to write a libretto based on this subject. Once free from working on Rigoletto, he started to think about the opera which would be entitled Il Trovatore.
As Verdi and Cammarano worked in different places, between the two of them there was an intense correspondence to work on the draft. Once the composer had read the libretto, he offered some suggestions for some changes to be made, and continued to do this until, little by little, the libretto started to take shape . He was particularly interested in loyalty towards the Spanish story, as he was fascinated by the originality and peculiarity of the storyline.
In the winter between 1851 and 1852 Verdi and Strepponi moved to Paris, where the musician endured a particularly busy period. He worked on Il Trovatore, had signed a contract with the Opéra de Paris for a new opera Les Vêpres Siciliennes and also assisted with the theatrical adaptation of La Dame aux Camélias, by Alexandre Dumas Junior which had inspired him to write La Traviata. In March 1852 the Maestro returned to Busseto, with Giuseppina, and he continued to work on Il Trovatore, even though his work was continuously interrupted by precarious health conditions of his librettist and his father (his mother had died the previous year). He also corresponded with Francesco Maria Piave to work on the libretto for La Traviata.
Unfortunately, in July of the same year, Cammarano died. The libretto wasn't complete at that stage, so the poet Leone Emanuele Bardare from Naples was entrusted with the job of finishing it using the notes which had been left by the previous author as a guideline. The birth of the libretto suffered, therefore, considerably, but fortunately the music took a lot less time to compose: it was done in the course of one month in November 1852. This was probably because the project had already been clear in the musician's mind for a year at that stage.
Once the final obstacle had been overcome, Verdi had to find a theatre where he could stage the opera. Initially, being aware of the link between Cammarano and Naples, he had thought about the Teatro San Carlo, but then he decided to choose a theatre which had more appropriate artists available. Finally he came to a satisfactory agreement with The Apollo Theatre in Rome, and the date of the première was fixed for January 19th, 1853.
This turned out to be a success without precedent. The public was very enthusiastic. La Gazzetta Musicale described it as a merited triumph and Il Trovatore was defined as a masterpiece, as it is considered even now.