Cleanthes. Known as Kassios; son of Phanias; from Assos; pupil of Krates and later of Zeno, whose successor he became. He was mentor of the philosopher Chrysippus of Soloi and of Antigonos the king. This man was at first a boxer, but after he had gone to Athens he fell in love with philosophy and became so hard-working that he was even called a second Herakles. For having no means of supporting himself, at nights he used to draw water for pay and during the day he worked at his studies and his books. Hence he got the nickname “Phreantles”. He wrote a lot of works.