- 1744 
- Spanish translation Near the altar is a golden image of the Goddess. Priests are in their solemnities, as after a sacrifice newly offer'd; flames arise from the altar, and the statue of Juno is seen to bow. Cadmus, King of Thebes, his daughters Semele and Ino, and Prince Athamas of Boeotia have assembled with priests: the marriage of Semele and Athamas is to be solemnized and the approbation of Juno, goddess of marriage, is noted and celebrated (Lucky omens). But all is not well. Cadmus and Athamas are both constrained to plead with Semele, whose unwillingness to proceed with the ceremony is plain. Semele begs help from Jupiter (Oh Jove! in pity), either, she says, 'to incline me to comply, or help me to refuse'. Athamas construes her behaviour as actuated by her love for him and calls on Hymen to assist his pleas (Hymen, haste). It is now Semele's sister Ino who delays the ceremony by expressing her sorrow: she herself is in love with Athamas and loath to lose him to Semele. None of the others comprehends, however, and they express only puzzlement and sympathy at her distress (Why dost thou thus untimely grieve).
Thunder is heard in the distance and the fire on the altar wanes. The priests note the bad omens (Avert these omens, all ye pow'rs! ) and the fire rekindles. But again it fades. Athamas pleads to Juno, and Semele to Jupiter. A loud clap of thunder is heard and the altar sinks. Fearing Jupiter's wrath, all except Ino and Athamas flee (Cease your vows). Athamas mistakes Ino's emotion for mere sympathy and upbraiding (You've undone me - With my life I would atone).
Cadmus, in mournful mood, returns with his attendants. He tells of the astonishing events that have just taken place: how Semele, surrounded by flames, was seized by a mighty eagle and snatched heavenward, leaving a diffusion of 'Celestial odour and ambrosial dew'. Priests and Augurs enter, but the doom Cadmus expects is not forthcoming; rather, they sing of mirth and triumph and tell him to cease his mourning (Hail, Cadmus, hail!). From a distance Semele's voice is heard (Endless pleasure, endless love); her song is taken up by the priests and the people.
Act 2
Juno, queen of the gods as well as goddess of marriage, and her attendant messenger, Iris, enter. Iris tells Juno about the 'new-erected palace' that Jupiter has provided for Semele on Mount Cithaeron (There, from mortal cares retiring). Juno is incensed at her husband's new love and swears an oath of vengeance, not only on Semele but on all 'Agenor's curst race' (Jupiter's previous love had been Europa, daughter of the Phoenician king Agenor and aunt to Semele). Iris warns Juno of the dragons that protect Semele's palace; Juno determines to call on Somnus, god of sleep, who can seal the 'wakeful dragons' eyes' (Hence, Iris, hence away).
An apartment in the palace of Semele; she is sleeping, Loves and Zephyrs waiting.
Semele, waking, calls on sleep to return and restore her erotic 'visionary joys' (Oh sleep, why dost thou leave me?). Jupiter, in human form, enters and reassures her (Lay your doubts and fears aside); she responds amorously (With fond desiring). All sing of the pains and joys of love (How engaging, how endearing).
But Jupiter detects a certain discontent in Semele, which she explains as the consequence of her mortal state in a world of deities. He is disturbed at her dangerous aspirations to immortality (I must with speed amuse her). All sing in praise of Cupid (Now Love, that everlasting boy). As a distraction for Semele, Jupiter dispatches his winged Zephyrs to fetch Ino, her sister, from Thebes and bring her as a companion. He then turns the scene into Arcadia and celebrates rural delights (Where'er you walk).
Ino arrives and describes to Semele her unusual journey and the sweet music she heard (But hark! The heav'nly sphere turns round); the sisters, then everyone, praise the joys of music (Bless the glad earth with heav'nly lays!).
Act 3
The cave of Sleep; the God of Sleep lying on his bed. A soft Symphony is heard afterwards. Juno calls Somnus to wakefulness. He is reluctant to stir (Leave me, loathsome light!). She renews her call, mentioning the name of Somnus's favourite nymph, Pasithea, to arouse him; he wakes and sings of his delight in the nymph (More sweet is that name). Juno commands him to instruct his attendant Morpheus to provide Jupiter with a dream 'in shape of Semele, But far more beautiful, And more alluring', to arouse his desire to such a pitch that he can refuse no favour she might ask as a condition for her love; further, Juno demands that Somnus hand over his leaden rod of sleep so that she can subdue the dragon sentinels and Ino, whom she intends to impersonate. Somnus duly complies (Obey my will - All I must grant).
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).
| Jupiter | Tenor | M-M | King of the gods |
| Cadmus | Bass | M-VL | King of Thebes |
| Semele | Soprano | F-H | Daughter to Cadmus, lover of Jupiter |
| Athamas | Alto | M-VH | Prince of Bœotia, in love with and designed to marry Semele |
| Ino | Mezzosoprano | F-M | Sister to Semele, in love with Athamas |
| Somnus | Bass | M-VL | God of Sleep |
| Apollo | Tenor | M-M | God of Prophecy |
| Juno | Mezzosoprano | F-M | Queen of the gods and Goddess of Marriage |
| Iris | Soprano | F-H | Messenger of Gods |
| High priest | Bass | M-VL |
| Act 1: | Scn 1: | Hymen, haste, thy torch prepare! |
| Oh Jove, in pity teach me which to choose | ||
| Act 2: | Hence, hence, Iris hence away! | |
| Oh sleep, why dost thou leave me? | ||
| Where'er you walk | ||
| Act 3: | Leave me, loathsome light | |
| Myself I shall adore | ||
| I am ever granting, you always complain | ||
| Above measure is the pleasure | ||
| No, no, I’ll take no less | ||
| Despair no more shall wound me |