Amadigi di Gaula, HWV.11

Amadigi, a Paladin, and Dardano, the Prince of Thrace, are both enamoured with Oriana, the daughter of the King of the Fortunate Isles. Oriana prefers Amadigi in her affections. Also attracted to Amadigi is the sorceress Melissa, who tries to capture Amadigi's affections by various spells, pleadings and even threats. Amadigi confronts various spirits and furies, but rebuffs them at practically every turn. One particular vision at the "Fountain of True Love", however, of Oriana courting Dardano upsets Amadigi to the point that he faints. Oriana sees Amadigi prostrate, and is about to stab herself with his sword when he awakens. He immediately berates her for her apparent betrayal of him, and in his turn tries to stab himself.

Still alive, Amadigi continues to resist the advances of Melissa. Melissa then makes Dardano look like Amadigi, to deceive Oriana. Oriana follows Dardano, in the visage of Amadigi, to beg his pardon. Dardano exults in the attention of Oriana, and in an impulsive moment, challenges Amadigi to single combat. In the duel, Amadigi kills Dardano. Melissa accuses Oriana of stealing Amadigi from her, and calls upon dark spirits to assault Oriana, who resists all of Melissa's incantations.
Dardano's celebrated aria Pena tiranna io sento al core from Act 2 is notable for its prominent bassoon part and its chord sequence based on the circle of fifths or, rather, circle of fourths. The introduction is shown in the score as one of the Baroque examples.

Amadigi and Oriana have been imprisoned by Melissa. The two lovers are willing to sacrifice themselves for each other. Though desirous of revenge, Melissa cannot quite yet kill Amadigi, but torments him by prolonging his confinement in chains. Amadigi and Oriana ask Melissa for mercy. Melissa summons the ghost of Dardano to assist her in her revenge, but the ghost says that the gods are predisposed to protect Amadigi and Oriana, and that their trials are nearly done. Rejected on all levels, by the gods, the underworld spirits, and Amadigi, Melissa takes her own life, with one final plea to Amadigi to feel a shade of pity for her. In the manner of a deus ex machina, Orgando, uncle of Oriana and a sorcerer himself, descends from the sky in a chariot and blesses the union of Amadigi and Oriana. A dance of shepherds and shepherdesses concludes the opera.