Cleanthes (/kliˈænθiːz/; Greek: Κλεάνθης Kleanthēs; c. 330 BC – c. 230 BC), of Assos, was a Greek Stoic philosopher and the successor to Zeno as the second head (scholarch) of the Stoic school in Athens. Originally a boxer, he came to Athens where he took up philosophy, listening to Zeno's lectures. He supported himself by working as water-carrier at night. After the death of Zeno, c. 262 BC, he became the head of the school, a post he held for the next 32 years.