Stoics and Epicureans. Reference is made in to certain philosophers belonging to these celebrated sects as having 'encountered' Paul at Athens.
The Stoics derive their name from stoa, 'a porch;' because their founder Zeno (who was born from 360 to 350 years B.C.) was accustomed to teach in a certain porch at Athens.
The Epicureans were named after their founder Epicurus, who is said to have been born at Athens B.C. 344, and to have opened a school (or rather a garden) where he propagated his tenets, at a time when the doctrines of Zeno had already obtained credit and currency.