Ferrando and his men, soldiers of Count di Luna, fortify themselves after a vicious battle in Spanish Aragon. To keep the men alert and on guard, Ferrando reminds the men of the reason they fight: the story of the two sons of the former Count (father of the current Count). Long ago an old traveling peasant woman was accused of bewitching the Count’s younger son, still an infant, who had turned sick. The witch was burned. In revenge, the woman’s daughter abducted the sickly baby and beside the witch’s bones were found the charred remains of a child. The old Count never believed his son had been killed and, on his deathbed, made his surviving son swear an oath that he would never give up the search for his younger brother. Ferrando, who witnessed these events, swears that he would recognize the witch’s daughter to this day.
Elsewhere in the palace, Leonora, a lady-in-waiting to the princess, tells her friend Inez about a mysterious troubadour who serenades her each night.
Count di Luna, who is infatuated with Leonora, watches her lustfully in secret. As the troubadour begins serenading Leonora, she rushes towards his voice. But in the darkness, she mistakes the Count for her love. The troubadour corrects her mistake by revealing himself: Manrico, champion of the rebel army. The Count challenges him to a duel.
As dawn rises on a rebel encampment, Manrico’s rebels sing the Anvil Chorus, working endlessly to create more weapons for the continuing war. Azucena, a troubled old woman, sings a haunting story about an inn