Bk I:722-746 Io is returned to human form.
Saturnia took his eyes and set them into the feathers of her own bird, and filled the tail with star-like jewels. Immediately she blazed with anger, and did not hold back from its consequences. She set a terrifying Fury in front of the eyes and mind of that "slut" from the Argolis, buried a tormenting restlessness in her breast, and drove her as a fugitive through the world. You, Nile, put an end to her immeasurable suffering. When she reached you, she fell forward onto her knees on the riverbank and turning back her long neck with her face upwards, in the only way she could, looked to the sky, and with groans and tears and sad lowing seemed to reproach Jupiter and beg him to end her troubles. Jupiter threw his arms round his wife's neck and pleaded for an end to vengeance, saying, "Do not fear, in future she will never be a source of pain," and he called the Stygian waters to witness his words.
As the goddess grows calmer, Iore gains her previous appearance, and becomes what she once was. The rough hair leaves her body, the horns disappear, the great eyes grow smaller, the gaping mouth shrinks, the shoulders and hands return, and the hooves vanish, each hoof changing back into five nails. Nothing of the heifer is left except her whiteness. Able to stand on two feet she raises herself erect and fearing to speak in case she lows like a heifer, timidly attempts long neglected words.