Dialogues of the Gods (15.2)

Europa in her play had come down to the beach with her companions, and Zeus took the shape of a bull, and started playing with them, looking magnificent, for he was all white with nice curly horns and gentle eyes. Well, he too started skipping about on the beach, and bellowed most charmingly, so that Europa even dared to climb up on to him. Thereupon Zeus galloped off to the sea with her on his back, plunged in and began to swim; she was quite terrified, and clutched his horn with her left hand so as not to slip off, while she held her robe down against the wind with her right hand.