- 1744 - Opera seria Semele, alone, remains discontent (My racking thoughts by no kind slumbers freed). Juno enters, in the guise of Ino, holding a magic mirror; she lavishly praises what she calls Semele's 'divine perfection' and wonders whether Jupiter has consented to her becoming immortal. She shows Semele her image in the mirror, deceiving her into thinking herself far more beautiful than she is; Semele revels in it (Myself I shall adore). Juno advises her to take full advantage of her situation and to demand that Jupiter come to her bed not as a mortal but 'like himself, the Mighty Thunderer, In pomp of majesty and heav'nly attire': only thus, she says, could Semele become immortal. Semele thanks her; as Jupiter approaches, Juno retires, elated at having duped the 'vain wretched fool' into destruction.
Jupiter enters and makes to embrace Semele; she looks kindly on him but retires a little. He pleads for her love (Come to my arms, My lovely fair); she keeps him at a distance (I ever am granting). He presses her to ask anything she requires; before she responds, she demands that he swear an irrevocable oath, by the River Styx, that he will not refuse her. He does so, calling on Olympus to shake in witness; its distant rumblings are heard. She tells him that he is to come to her not in human shape but as Jupiter himself. 'Ah, take heed what you press', he exclaims; but Semele, imagining that he is merely reluctant to accord her immortality, will not give way (No, no, I'll take no less).
She goes to prepare herself. Jupiter, left alone, pensive and dejected, bitterly regrets his impetuous oath; for if he appears as the Mighty Thunderer 'she must a victim fall', for all that he may apply his 'softest lightning' and 'mildest melting bolt'. Juno delights in her triumph (Above measure, Is the pleasure).
The scene discovers Semele while a mournful Symphony is playing. She looks up and sees Jupiter descending in a cloud; flashes of lightning issue from either side and thunder is heard grumbling in the air. Semele realizes the consequences of her vanity and ambition (Ah me! Too late I now repent). Consumed by Jupiter's fire, she dies.
In Thebes, Ino - now returned - is with Cadmus, Athamas and priests; they have witnessed the demise of Semele as some kind of fiery storm (Oh terror and astonishment!). Ino relates that Hermes, messenger of the gods, has told her of Semele's fate, and also that Jupiter commands her and Athamas to wed; Athamas contentedly accepts the situation. A bright cloud descends and rests upon Mount Cithaeron, which opening, discovers Apollo seated in it as the God of Prophecy. Apollo predicts that a phoenix shall rise from Semele's ashes, a god more mighty even than Love - it will be Bacchus, god of wine. Everyone celebrates this fortunate outcome (Happy shall we be).