From The Wiccan Year by Judy Ann Nock

The sacred bull is an icon that appears in diverse mythologies across thousands of years and survives to this day in the constellation of Taurus. The bull features prominently in the cosmology of Mesopotamia, in the Persian Mithraic cult, and the cult of the Minotaur of Crete. Perhaps no other animal has been so closely linked with the gods and goddesses alike. From the sacred bull of Mithras, whose death created the cosmos, to the bull that slaughtered Tamus, the consort of the Goddess Ishtar, setting into motion the cycle of seasons, the bull is strongly identified with the genesis and fertility of the land. 

A fixed earth sign, Taurus carries a decided feminine energy. The many goddesses associated with Taurus include Isis, Aphrodite, Io, Maeve, and Seline. 

Another trade popularly associated with Taurus is the presence of artistic ability. this Association may have risen from the fact that some of the earliest known art in existence features images of the wild cattle, or aurocs, the predecessor of the modern domestic cattle. the paintings of aurocks in the caves of Lascaux in southwest France were believed to have been created sometime between 13,000 and 25,000 BC. Their presence a test to the great significance of the bulls in Paleolithic culture. 

Tropical astrology holds the sun to enter Taurus on April 21st and remain until May 21st bringing the energy of the sun through this Venus ruled constellation to the Beltane fires.