Zeno of Citium was a Greek philosopher who founded the school of philosophy known as Stoicism around the early 3rd century BCE. Born in Citium, a city on the island of Cyprus, he moved to Athens where he studied various philosophical teachings before developing his own ideas. Zeno emphasized the importance of virtue, reason, and living in harmony with nature. His teachings influenced many later philosophers, including Seneca, Epictetus, and Marcus Aurelius. Zeno's philosophy focused on self-control, resilience, and the belief that external events should not disturb one's inner peace. His work laid the foundation for Stoic thought, which remains influential today.