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
"Zeus" is the Greek continuation of *"," the name of the Proto-Indo-European god of the daytime sky, also called *' ("Sky Father"). The god is known under this name in the Rigveda (Vedic Sanskrit "Dyaus/Dyaus Pita"), Latin (compare "Jupiter", from "Iuppiter", deriving from the Proto-Indo-European vocative *'), deriving from the root *"dyeu"- ("to shine", and in its many derivatives, "sky, heaven, god").
Zeus is the only deity in the Olympic pantheon whose name has such a transparent Indo-European etymology.