Ovid
The Metamorphoses of Ovid, Book II (Fable. 10)
Ocyrrhoë, the daughter of the Centaur Chiron, attempting to predict future events, tells her father the fate of the child Æsculapius, on which the Gods transform her into a mare.

In the meantime the half-beast Chiron was proud of a pupil of Divine origin, and rejoiced in the honor annexed to the responsibility. Behold! the daughter of the Centaur comes, having her shoulders covered with her yellow hair; whom once the nymph Chariclo,74 having borne her on the banks of a rapid stream, called Ocyrrhoë. She was not contented to learn her father’s arts only; but she sang the secrets of the Fates. Therefore, when she had conceived in her mind the prophetic transports, and grew warm with the God, whom she held confined within her breast, she beheld the infant, and she said, “Grow on, child, the giver of health to the whole world; the bodies of mortals shall often owe their own existence to thee. To thee will it be allowed to restore life when taken away; and daring to do that once against the will of the Gods, thou wilt be hindered by the bolts of thy grandsire from being able any more to grant that boon. And from a God thou shalt become a lifeless carcase; and a God again, who lately wast a carcase; and twice shalt thou renew thy destiny. Thou likewise, dear father, now immortal, and produced at thy nativity, on the condition of enduring for ever, wilt then wish that thou couldst die, when thou shalt be tormented on receiving the blood of a baneful serpent75 in thy wounded limbs; and the Gods shall make thee from an immortal being, subject to death, and the three Goddesses76 shall cut thy threads.”

Something still remained in addition to what she had said. She heaved a sigh from the bottom of her breast, and the tears bursting forth, trickled down her cheeks, and thus she said: “The Fates prevent me, and I am forbidden to say any more, and the use of my voice is precluded. My arts, which have brought the wrath of a Divinity upon me, were not of so much value; I wish that I had not been acquainted with the future. Now the human shape seems to be withdrawing from me; now grass pleases me for my food; now I have a desire to range over the extended plains; I am turned into a mare, and into a shape kindred to that of my father. But yet, why entirely? For my father partakes of both forms.”

As she was uttering such words as these, the last part of her complaint was but little understood; and her words were confused. And presently neither were they words indeed, nor did it appear to be the voice of a mare, but of one imitating a mare. And in a little time she uttered perfect neighing, and stretched her arms upon the grass. Then did her fingers grow together, and a smooth hoof united five nails in one continued piece of horn. The length of her face and of her neck increased; the greatest part of her long hair became a tail. And as the hairs lay scattered about her neck, they were transformed into a mane lying upon the right side; at once both her voice and her shape were changed. And this wondrous change gave her the new name of Enippe.

Footnotes:

74. Chariclo.]—Ver. 636. She was the daughter of Apollo, or of Oceanus, but is supposed not to have been the same person that is mentioned by Apollodorus as the mother of the prophet Tiresias.

75. A baneful serpent.]—Ver. 652. This happened when one of the arrows of Hercules, dipped in the poison of the Lernæan Hydra, pierced the foot of Chiron while he was examining it.

76. The three Goddesses.]—Ver. 654. Namely, Clotho, Lachesis, and Atropos, the ‘Parcæ,’ or ‘Destinies.’