During the Age of Taurus (roughly from 3000 BCE to 800 BCE), the bull and the calf were venerated. As this Age transitioned to Aries, the Mithraic Mysteries arose where the cosmic Christ was sought as one overcame the bull within:Mithras

Note the symbol of the snake. Mithraism apparently grew out of Persia and became popular throughout much of the Roman empire just before the spread of Christianity.