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.
Spear
In classical Greek mythology Zeus' bolts of lightning may be interpreted as a symbolic spear. Some would carry that interpretation to the spear that frequently is associated with Athena, interpreting her spear as a symbolic connection to some of Zeus' power beyond the Aegis once he rose to replacing other deities in the pantheon. Athena was depicted with a spear prior to that change in myths, however. Chiron's wedding-gift to Peleus when he married the nymph Thetis in classical Greek mythology, was an ashen spear as the nature of ashwood with its straight grain made it an ideal choice of wood for a spear.