As he spent the whole day in studying philosophy with no visible means of support, he was summoned before the Areopagus to account for his way of living.

The judges were so delighted by the evidence of work which he produced, that they voted him ten minae, though Zeno would not permit him to accept them.

His power of patient endurance, or perhaps his slowness, earned him the title of "the Ass" from his fellow students, a name which he was said to have rejoiced in, as it implied that his back was strong enough to bear whatever Zeno put upon it.

[2] Simplicius, writing in the 6th century AD, mentions that a statue of Cleanthes was still visible at Assos, which had been erected by the Roman Senate.

[4] Cleanthes was an important figure in the development of Stoicism, and stamped his personality on the physical speculations of the school, and by his materialism gave a unity to the Stoic system.

[5] He wrote some fifty works, of which only fragments have survived preserved by writers such as Diogenes Laërtius, Stobaeus, Cicero, Seneca and Plutarch.

[18] This, according to him, is true freedom of will not acting without motive, or apart from set purpose, or capriciously, but humbly acquiescing in the universal order, and, therefore, in everything that befalls one.

[18] The direction to follow Universal Nature can be traced in his famous prayer: Lead me, Zeus, and you too, Destiny, To wherever your decrees have assigned me.

[20] Cleanthes also appears in José Enrique Rodó's essay Ariel, in which he is depicted as meditating on the teachings of Zeno as he carried water all through the night.