Christianity in the Roman Empire. Roman religion at the beginning of Roman Empire (27 BC – 476 AD) was polytheistic and local. Each city worshiped its own set of gods and goddesses that had originally been derived from ancient Greece and become Romanized.
Two new elements were added to political life at the beginning of the Middle Ages. These were the doctrines of Christianity, as they developed in contact with Roman philosophy and institutions, and the political ideas of the Teutonic barbarians who overthrew the Roman Empire.
The ideas of the Teutons worked themselves out mainly in the form of institutions, and did not affect political philosophy until the close of the medieval period. On the other hand, the establishment of the Christian religion and the development of the Christian church became cardinal influences on medieval political thought.
Christianity, with its Stoic doctrine of the equality of men in the sight of God and its emphasis on the supreme value of the individual, appeared just after the Roman world was reorganized under a monarchy. It originated among a despised people in an obscure part of the empire; and as long as the Roman power was strong, it grew slowly, appealing in the main to the lowest ranks of society.
As the empire declined, it spread more rapidly, until, in the early part of the fourth century, it was the religion of the dominant classes in the Roman world, and was on an equal legal footing with paganism. When Constantine made it the official worship of the state, it rapidly triumphed over the dying pagan beliefs, and by the close of the fourth century it was the only legal religion in the Roman world. Through the zeal of its adherents it also made considerable headway among the Teutonic barbarians who were soon to destroy the empire.
The sanction of the Christian church was thus added to the authority of the emperor, and the belief became firmly established that the Roman authority was divinely ordained to rule the world and that it was to last forever. These ideas remained fundamental in medieval political thought.
At first the church was organized on a democratic and local basis, but the churches located in the important cities and those that were founded by the apostles enjoyed a certain preeminence. The Roman church and its bishop were especially prominent.
After Christianity became the official religion of the Roman Empire, it was immediately drawn into politics, The emperor exercised ultimate authority in religious matters and the organization of the church followed that of the government.
During the last century of the empire, however, the ecclesiastical authorities gained power at the expense of the political ones. Most of the emperors were weak, the church had able men in its chief positions, and the doctrines of the church were especially attractive during this period of turmoil and social decadence.
With the fall of the Western Empire, the political institutions of Rome were destroyed or seriously modified, though the organization of the church remained untouched.
Accordingly, the church represented the Roman tradition, emphasized the principle of unity during the period of anarchy following the invasions, and was compelled to take over an increasing amount of temporal authority in its effort to maintain order and peace.
The bishops became recognized officials of government in the barbarian kingdoms and virtually controlled some of the most important cities. The burden of secular work thus thrown upon the church further centralized authority in the organization that centered around the bishop of Rome.
In the Eastern Empire, which survived the invasions, the church remained subordinate to the state. Its energies were devoted to philosophical speculations concerning obscure questions in theology rather than to the practical problems of converting and controlling barbarians in a world whose political system had gone to pieces.