Chrysippus was a prominent ancient Greek philosopher who lived from 280 to 206 BCE. He is best known for his contributions to Stoicism, a school of thought that emphasizes rationality and virtue as the path to a good life. Chrysippus expanded on the ideas of earlier Stoics, such as Zeno of Citium, and developed a comprehensive system of logic and ethics. Chrysippus wrote extensively, producing over 750 works, although most of them have been lost. His teachings focused on the importance of living in harmony with nature and understanding the universe's rational structure. He is often credited with solidifying Stoicism as a major philosophical movement in ancient Greece and Rome.