Zeno of Citium was a philosopher who lived from approximately 334 to 262 BCE. He was born in Citium, Cyprus, and moved to Athens as a young man to study. There, he learned from teachers of several schools, including the Cynic Crates. Around 300 BCE, Zeno began teaching his own philosophy in a public colonnade known as the Stoa Poikile. His school of thought took its name, Stoicism, from this location. He was highly respected in Athens and lived there until his death.

Zeno founded the Stoic school, establishing its core framework. He divided philosophy into three interconnected parts: logic, physics, and ethics. His central teaching was that the goal of life is to live in agreement with nature, which he identified with a rational divine principle governing the cosmos. He taught that virtue, based on wisdom and self-control, is the only true good. None of Zeno’s own writings survive intact. His ideas are known today through fragments and reports by later authors. Some of his known works include Republic, On Nature, and On Life According to Nature.

As the founder of Stoicism, Zeno’s historical importance is immense. His school became one of the most influential in the ancient world. His successors, especially Chrysippus, developed his ideas into a comprehensive system. Stoic philosophy later profoundly shaped Roman thought and was practiced by famous figures like Seneca, Epictetus, and the emperor Marcus Aurelius.