Bk IX:764-797 Isis transforms Iphis.
With these words, she stopped speaking. The other girl was no less on fire, and prayed, Hymen, that you would come quickly. Telethusa, afraid of what she sought, merely put off the day: now lengthening the delay through pretended illness, now, frequently, using omens and dreams as an excuse. But eventually every pretext was exhausted, the date for the delayed marriage ceremony was set, and only a day remained. Then Telethusa took the sacred ribbons from her own and her daughter Iphis's head, so that their hair streamed down, and clinging to the altar, cried: "Isis, you who protect Paraetonium, Pharos, the Mareotic fields, and Nile, divided in its seven streams, I pray you, bring help, and relieve our fears! Goddess, I saw you once, you, and those symbols of you, and I knew them all, accompanied by the jingling bronze of the sistrum, and imprinted your commands on my remembering mind. That my daughter looks on the light, that I have not been punished, behold, it was your purpose, and your gift. Gladden us with your aid. Have pity on us both!"
Tears followed words. The goddess seemed to make the altar tremble (it did tremble), and the doors of the temple shook, her horns, shaped like the moon's crescents, shone, and the sistrum rattled loudly. Not yet reassured, but gladdened by the auspicious omen, the mother left the temple. Iphis, her companion, followed, taking larger paces than before; with no whiteness left in her complexion; with additional strength, and sharper features, and shorter, less elegant hair; showing more vigour than women have. Take your gifts to the temple, Iphis: rejoice, with confidence, not fear! You, who were lately a girl, are now a boy!
They take their gifts to the temple, and add a votive tablet: the tablet has this brief line:
IPHIS PERFORMS AS A BOY, WHAT HE PROMISED, AS A GIRL.
The next day's sun reveals the wide world in its rays, when Venus, and Juno, joined with Hymen, come, to the marriage torches, and Iphis, the boy, gains possession of his Ianthe.