The White Bull
The story is based on the Greek mythological tale of Europa and the bull, where the white bull is the king of the Greek gods, Zeus, in disguise. Zeus, the sky and thunder god of the Olympic pantheon, often wore a disguise when romantically pursuing mortal women, so as to avoid the eye of his wife and sister, Hera.
Zeus
The oracle of Ammon at the Siwa Oasis in the Western Desert of Egypt did not lie within the bounds of the Greek world before Alexander's day, but it already loomed large in the Greek mind during the archaic era: Herodotus mentions consultations with Zeus Ammon in his account of the Persian War. Zeus Ammon was especially favored at Sparta, where a temple to him existed by the time of the Peloponnesian War.