Zeno of Citium (334–262 BCE)
Zeno of Citium (sv: Zenon av Kition) founded a complete school of philosophy, called Stoicism because he taught at a porch (stoa) in downtown Athens.
Not the originator of Zeno's paradox, that's a different Zeno.
When Zeno first came to Athens, he asked a vendor where he might find a man like Socrates (469–399 BCE). A Cynic by the name of Crates was just passing by, and the vendor said "Follow that man". Zeno did, and learned much from Crates, in particular his disregard for common values.
Like most Greeks, Zeno admired Socrates, but he did not agree with the directions taken by Plato and Aristotle, and combined the character of Socrates with the philosophy of Heraclitus (535–475 BCE), instead. In ways, Stoicism is the philosophy most similar to that of Socrates himself. See for example the Academic Sceptics' stance that you could not know anything for certain, while Socrates and the Stoics would say that there is a class of things you can know for certain. (Looks like rationalists vs. empiricists again…).
Much of Greek philosophy ended up absorbing aspects of each other in the Roman period, so the distinctions mattered less.