The story
From either or both of the synonymous Ancient Greek nouns στασιάρχης (stasiárkhēs) and/or στασίαρχος (stasíarkhos, “chief of a band”; “leader in sedition”), from στάσις (stásis, “part”, “band”; “sedition”) + either -άρχης (-árkhēs, “-ruler”) or ἀρχός (arkhós, “leader”).
Etymology from Wiktionary, CC BY-SA 4.0.