MIA: Encyclopedia of Marxism: Glossary of Organisations
The Stoics saw that unhappiness and fear arose from the impact of things outside one's control. They said that everything outside of our control was ordained by God, but one's own will was a particle of God - the "Divine Fire" which possessed the property of Reason. Zeno said that cognition of the world took place through sensation, but sensations gave true knowledge only if the image was stable and perfect. Throughout Graeco-Roman antiquity, there was a struggle between the "idealist" trend of the Stoics and the "materialist" trend of the Epicureans.
See Hegel on the Stoics.