Zeno was the founder of Stoic philosophy in Athens. He was born in Citium on the island of Cyprus. It is reported that he was originally a merchant, but was shipwrecked and lost all his property traveling to Athens in 314 BC. He stayed there, and took up the study of philosophy, meeting his students on a stoa (porch), from which the name stoic came.

Zeno taught that it is foolish to try to shape circumstances to our desires. The world process is not like a blindly running machine. Instead, a divine intelligence guides and governs it, and directs all things ultimately toward what is good. Wise people will "follow nature" and fit their desires to the pattern of events. They will find happiness in freedom from desire, from fear of evil, and in knowing that they are in tune with the divine purpose directing all things. The Stoic philosophy spread to Rome and flourished there for several centuries after the birth of Christ.

He was a student of the Cynic philosopher Crate of Thebes and of the Platonist Xenocrates.

Stoic philosophy flourished from about 300 BC to 300 AD. It began in Greece and later spread to Rome. The Stoic philosophers believed that all people have within themselves reason, which relates each person to all the other people and to the Reason (God) that governs the universe. This belief provided a theoretical basis for cosmopolitanism - the idea that people are citizens of the world rather than of a single nation or area. This view also stimulated the belief in a natural law that stands above civil law and provides a standard by which human beings' laws may be judged.

The Stoics felt that people achieve their greatest good - which is happiness - by following reason, freeing themselves from passions, and concentrating only on things they can control.

The Stoic philosophers had their greatest influence on law, ethics, and political theory, but they also formulated important views on logic, the theory of knowledge, and natural philosophy. The early Stoics, particularly Chrysippus, were interested in logic and natural philosophy as well as ethics. The later Stoics, especially Seneca, Marcus Aurelius and Epictetus, emphasized ethics.

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