Επίκτητος (Epictetus) was a Greek Stoic philosopher who lived from 55 to 135 AD. He emphasized the importance of personal responsibility and the idea that individuals can control their reactions to external events. His teachings focus on distinguishing between what is within our control and what is not, encouraging people to accept the latter with equanimity. His ideas were recorded by his student, Arrian, in works such as the Discourses and the Enchiridion. Epictetus believed that true freedom comes from mastering one's desires and emotions, leading to a life of virtue and inner peace, central tenets of Stoicism.