Stoics thought of the virtuous life as a relation of the soul to God, rather than as a relation of the citizen to the State. They thus prepared the way for Christianity, which, like Stoicism, was originally unpolitical, since, during its first three centuries, its adherents were devoid of influence on government. Social cohesion, during the six and a half centuries from Alexander to Constantine, was secured, not by philosophy and not by ancient loyalties, but by force, first that of armies and then that of civil administration. Roman armies, Roman roads, Roman law, and Roman officials first created and then preserved a powerful centralized State. Nothing was attributable to Roman philosophy, since there was
none.

During this long period, the Greek ideas inherited from the age of freedom underwent a gradual process of transformation. Some of the old ideas, notably those which we should regard as specifically religious, gained in relative importance; others, more rationalistic, were discarded because they no longer suited the spirit of the age. In this way the later pagans trimmed the Greek tradition until it became suitable for incorporation in Christian doctrine.

Christianity popularized an important opinion, already implicit in the teaching of the Stoics, but foreign to the general spirit of antiquity I mean, the opinion that a man's duty to God is more imperative than his duty to the State. 1 This opinion that "we ought to obey God rather than Man/' as Socrates and the Apostles said survived the conversion of Constantine, because the early Christian emperors were Arians or inclined to Arianism. When the emperors became orthodox, it fell into abeyance. In the Byzantine Empire it remained latent, as also in the subsequent Russian Empire, which derived its Christianity from Constantinople. But in the West, where the Catholic emperors were almost immediately replaced (except in parts of Gaul) by heretical barbarian conquerors, the superiority of religious to political allegiance survived, and to some extent still survives.

The barbarian invasion put an end, for six centuries, to the civilization of western Europe. It lingered in Ireland until the Danes destroyed it in the ninth century; before its extinction there it produced one notable figure, Scotus Erigena. In the Eastern Empire, Greek civilization, in a desiccated form, survived, as in a museum, till the fall of Constantinople in 1453, but nothing of importance to the world came out of Constantinople except an artistic tradition and Justinian's Codes of Roman law.