Taurus, located between Aries and Gemini, is a very ancient constellation, the bull was worshipped as a symbol for immense power and cattle in general as the providers of food and milk, thus getting associated with nourishment, growth and physical well-being.
The sacred bull or bull god of ancient Egypt was Apis, taken for another incarnation of Ptah or of Osiris, shown as a bull with the golden sun between its horns. Every black bull with a white sign on its forehead was taken as a personification of Apis, watched by priests who thought they could detect omens in its behaviour. When the bull died, it was buried with much honors and a new one was to be found to take its place. The Apis cult was very famous in ancient times, closely connected with the Ptah cult and later also present in the Greek and Roman culture.
The Egyptian zodiac image also implies the cow goddess Hathor which was the
goddess of beauty, love and happiness, representing all the riches seen in cattle as
the providers of nourishment. Although generally friendly and tender, Hathor could
easily turn into a fierceful warrior of enormous strength, therefore it wasn't very
wise to displease her.
Hathor was also shown with the sun between her horns, so it is not always easy to part her from Apis. Since the Egyptian zodiac shows the constellation of Sirius also as a cow, some archaeologists believe that Sirius is represented by Apis and Taurus by Hathor.
With the Greek, the legend became popular that Taurus was Zeus disguised as a beautiful white bull, persuading Europa, the daughter of Agenor and sister of Cadmus, to mount his back and then swam to Crete with him - one of the many amusing stories in which Zeus was after beautiful lovers while driving his wife Hera up the wall.