The liberal arts (Latin: artes liberales) are those subjects or skills that in classical antiquity were considered essential for a free person (Latin: liberalis, "worthy of a free person") to know in order to take an active part in civic life, something that (for Ancient Greece) included participating in public debate, defending oneself in court, serving on juries, and most importantly, military service. Grammar, logic, and rhetoric were the core liberal arts, while arithmetic, geometry, the theory of music, and astronomy also played a (somewhat lesser) part in education.