Cleanthes

Cleanthes (c. 330–230 BCE) succeeded Zeno as head of the Stoa, giving its physics a fervent, almost devotional cast. His Hymn to Zeus — addressing the supreme god as the rational law pervading all things — is the noblest religious poem the school produced.

A former boxer who drew water by night to study by day, he held the cosmos to be a living, divine fire, and was succeeded in turn by his pupil Chrysippus.