In general “classic” is used to mean “a work of enduring value.” However, as you indicate classic works, such as Antigone, are products of the Classical Period (more broadly, of the Axial Age). Such works constitute the classics, meaning not only that their value endures but that they are fundamental to how we understand ourselves.
In general “classic” is used to mean “a work of enduring value.” However, as you indicate classic works, such as Antigone, are products of the Classical Period (more broadly, of the Axial Age). Such works constitute the classics, meaning not only that their value endures but that they are fundamental to how we understand ourselves.