Epicureanism is an ethical school of thought founded by Epicurus during the Hellenistic Period.
Epicureanism is primarily concerned with pleasure, claiming that happiness is the highest form of good. Therefore, to live an ethical life is to live on which maximizes happiness. It is a form of hedonism, but, unlike the colloquial understanding of the word, it advocates for a simple life and absence of pain over grand indulgences.
The primary challenger to this school of thought was Stoicism.