Pythagoras was born off the coast of Turkey on the Island of Samos in the 6th century BC. He is most famous for his well-known proposition about right angle triangles, known as the Pythagorean theorem. Having spent time in Egypt and Babylon, much of his main philosophical teachings are a combination of ideas expressed in the places he traveled to.
Pythagoras preached the soul as being abstract and immortal. A soul is within all living creatures, and therefore all creatures, man or beast deserve to be treated compassionately. The soul was said to pass between lives into different living creatures. Therefore in eating the flesh of an animal, one could be eating the flesh of a deceased cousin. This was somewhat revolutionary for a world in which religious ritual was centered on animal sacrifice. He also believed in the concept that an eternal world which was revealed to the intellect through continuous ascetic routines rather then the senses.
For two hundred years following Pythagoras death a religion made up of followers of his teachings persisted. As a religious practice of it dissipated, but the teachings were responsible for influencing the likes of Plato and Socrates.
Plato frequently makes reference to the migration of souls across species lines. This is in no way a proof that he himself was a Vegetarian, but it does show that one of western philosophies premier philosophers had a regard for animals with certain sensitivity. In Plato's Republic, there is a documented dialogue between Socrates and his student Glaucon. Socrates points out that the eating of animals causes one state to go to war with the other. Cattle were considered great wealth, and states would fight with each other to obtain cattle. Meat was valued as such a luxury that men were willing to die for it. Socrates suggested that the consumption of cattle is somewhat gluttonous rather then of necessity. He suggests refraining from meat would lead to a world with less conflict and greater opportunity for peace. Another great Greek philosopher was Theophrastus. A contemporary of Aristotle, his writings clearly state that if plants and vegetables are abundant there is no need to eat meat. Theophrastus speculates that people only began to eat meat when crops were destroyed in war. The Bible, arguably the most influential document for western philosophy, speaks of a world that begins with a euphoric harmony in which all walks of life are vegetarian. " And God said,...