The Stoics were a school of philosophy founded by the Greek philosopher Zeno of Citium in the early 3rd century BC. They believed that virtue, the highest good, was based on knowledge, and that the wise lived in harmony with the divine Reason that governed nature. The Stoics followed Zeno's teachings and developed their own system of ethics, logic, and natural philosophy. They believed that all people should strive to live in accordance with nature, and that this would lead to inner peace and happiness.