Hellenistic school (founded by Zeno of Citium, ~300 BCE) holding that virtue is the only true good and that flourishing comes from living in accord with reason and nature.
Key tenets
Dichotomy of control: focus on what is up to you (judgements, will); accept the rest.
Virtue (wisdom, justice, courage, temperance) is the sole good.
Emotions arise from judgements; correct the judgement, correct the emotion.