Act I

The magus Zoroastro studies the stars, divining in their patterns that the errant Carolingian knight Orlando shall not always be a foe to valour and duty (Gierolifici eterni).
Orlando appears, torn between his ordained role as warring knight and his love for the princess Angelica, Queen of Cathay (Stimulato dalla Gloria). Zoroastro challenges Orlando to return to his true path; after showing Orlando disturbing images of his downfall and spiritual decay, he exhorts him to abandon Venus and follow Mars (Lascia Amor). After a moment’s hesitation, Orlando resolves to have both (Non fu già).

Dorinda, a shepherdess, contemplates the beauty of nature, and yet feels the pangs of love stirring within her. She has been giving shelter to Angelica and the Moorish soldier Medoro, whom Angelica found near death and brought to the shepherdess. Orlando appears, rescuing the hapless Princess Isabella from her captors. Dorinda, mistakenly believing Orlando to be in love with Isabella, comments that she may well share something in common with him – but is it really love that she is feeling? (Ho un certo rossore)

Angelica appears, and recalls the moment she saw the injured Medoro for the first time (Ritornava al suo bel viso). She has fallen desperately in love with him, and the pair are now lovers. When Angelica has left Dorinda finds Medoro and expresses her fears that he may be more than just a friend to Angelica. Medoro explains to her that he owes Angelica his life and will soon leave with her; rather disingenously he reassures Dorinda that he will never forget her (Se’il cor mai ti dirà). Dorinda, knowing deep down that he is just flattering her, nevertheless decides to cheer herself up with his false words (O care parolette).

Zoroastro warns Angelica to fear the wrath of Orlando, should he ever discover that she loves someone else; seeing Orlando appproaching, he conceals himself, resolving to protect Angelica and Medoro. Angelica reveals herself to Orlando, seeking to find a way out of her situation: hoping that he may be in love with Isabella, she feigns jealousy to discover whether this may actually be the case. Orlando vigorously denies any love for Isabella, declaring Angelica to be his true love. Angelica, hoist by her own petard, orders Orlando never to help Isabella again, or Angelica will disappear forever from his life (Se fedel vuoi ch’io ti creda). Orlando dejectedly agrees, and vows to honour Angelica with countless trophies of war (Fammi combattere).

Medoro rushes in as Orlando leaves, and demands to know whom Angelica was with. Angelica explains, and knowing that he will never be a match for Orlando’s strength, tells him to save himself for love. She resolves to leave with Medoro and return to her Eastern kingdom to escape Orlando’s wrath. Dorinda enters and sees them in a passionate embrace. The couple can hide their love no longer, and reassure the dejected Dorinda that she too will one day find love (Consolati, o bella). Angelica gives Dorinda a jewel as a token of her thanks for Dorinda’s hospitality.

Act II

The curtain opens on a lovelorn Dorinda, dejectedly empathising with a nightingale’s sad melody (Quando spieghi tuoi tormenti). Orlando appears and demands to know why she had told Angelica that he was in love with Isabella. Dorinda denies it, and goes on to explain her sadness at Angelica and Medoro’s love for each other. When Orlando demands proof, she shows him the jewel that Angelica has given her. Dorinda pines that she now sees Medoro in every flower and in every tree (Se mi rivolgo al prato).

Orlando, devastated at this news, vows revenge on Angelica. Born under a magic spell of invulnerability, he implores heaven to kill him too (Cielo! Se tu’l consenti).

Zoroastro urges Angelica and Medoro to flee, promising to protect them on their journey. He nevertherless points to a moral that love can lead to ruin and sadness if the light of reason is not there to act as a guide (Tra caligini profonde).

Angelica and Medoro are saddened at having to leave the verdant caves and limpid streams where their love first blossomed. Medoro carves their names into the trees to preserve their memory there forever (Verdi allori).

Angelica still feels guilty at having lied to Orlando; she tells herself however that he will understand, that he must understand, as he too has been pierced by love’s arrow and will thus sympathise with her predicament (Non potrà dirmi ingrata). She too bids farewell to the plants and streams that had brought her such pleasure
(Verdi piante).

Orlando rushes in upon Angelica, vowing to kill her. Angelica pleads in vain for Medoro to rescue her. She tries to escape, and is rescued by Zoroastro’s genies, who sweep down from heaven on a cloud and whisk her away. Orlando, enraged, curses heaven and sinks down, crushed (Ah, stigie larve!). Madness sets upon him – all the fury he was to expend on Angelica now turns inward and he imagines himself a shadow, entering Hades. Hallucinating, he sees Medoro in the arms of Proserpina, the wife of Pluto, and runs to kill him, but suddenly notices that Proserpina is crying, and begs her to stop (Vaghe pupille). Anger boils up inside Orlando once more, but before he is able to do himself harm, Zoroastro appears and carries him off to safety.

Act III
Medoro, separated from Angelica in the confusion, returns to Dorinda’s hut and shamefacedly tells her that he would give her his heart if he could, but that it is no longer his to give (Vorrei poterti amar). Dorinda comments on the madness of love and the folly which it creates (Amore è qual vento).

Zoroastro appears and reaffirms the moral that reason is easily destroyed by love. He transforms the setting from a peaceful forest into a dark cave, setting the scene for Orlando’s eventual return to sanity (Sorge infausta una procella).

Angelica returns, and finds Dorinda crying. When asked why, Dorinda can barely tell her – the raging Orlando has destroyed her cottage, apparently burying Medoro in the rubble. Orlando appears and confronts Angelica, who, devastated, begs him to kill her (Finche prendi ancora il sangue). Orlando violently hurls Angelica into the cave,
which is suddenly transformed by Zoroastro into the Temple of Mars.

Orlando triumphantly declares himself to have ridden the earth of every monster and every evil spirit. Overcome by tiredness, he imagines himself drinking the opiate waters of the river of Lethe, and falls asleep (Gia l’ebro mio ciglio).

Zoroastro proclaims that the hour has come for Orlando’s sanity to be returned to him; a bird descends from the moon with a phial, and Zoroastro sprinkles the contents over Orlando. The knight awakes, and Dorinda regales him with the horrific deeds he commited while insane – killing Angelica and Medoro. Overcome with remorse, Orlando resolves to kill himself (Per far, mia diletta).

Angelica and Medoro appear, to Orlando’s joy, having been saved by Zoroastro. Angelica forgives Orlando for his actions, and Zoroastro begs him on behalf of the lovers for his blessing of their relationship. Orlando willingly concedes, and declares himself forever the servant of valour and war. Dorinda invites everyone back to her cottage to celebrate. All join in praise of the equal merits of love and valour (Trionfa oggi il mio cor).