When the imperial Church began the process of the missionizing Northern Europe they took over a process that had already been underway since as least the time of Julius Caesar’s encounter with the Germans.
The earlier process was not missionary work, the Ancient Romans were not spreading the faith. It was the work of bringing the Northern trines into the Roman Empire, it was the work of federalizing, or federating, from the Latin foederati.
Cicero gives us the earliest known use of the term foederati,[i] which the Romans used to classify the tribes of “barbarians” that were migrating South, into the Roman provinces, attracted by the stability of Roman society, and who sought a peaceful coexistence with the Romans as allies, instead of conflict, and war.
The foederati system allowed members of the federated tribes to serve in the Roman army, and after 20 years of service they could muster out with a portion of the rights of a Roman citizen, or even full citizenship if they had distinguished themselves.
For the migrating tribes of barbarians (Germanic people) the only alternative to becoming foederati was war with the Romans. War with the Romans had been the ruin of countless tribes, either one of those two choices, or remain beyond the reach of Roman power, beyond access to coveted Roman goods and markets.
When the Church took over this process, when missionization replaced federation, it systematized what had been a haphazard process. Both functions changed in relation to each other.
Traditional Missionary work, like that of Saint Paul in the first generation of Christian after the death of Jesus, resulted in the formation of grass-roots communities spread in urban centers throughout the Empire. Those communities eventually grew, becoming the most dominant party in the Roman Empire, In the early fourth century they received the support of the Army, under Saint Constantine, Constantine became the Emperor, and the Church became co-extensive with the Empire itself.
What immediately followed were two centuries of religious wars, conflict between opposing groups of Christians. By the time these conflicts were resolved, both the Church and the Empire were ready and eager for renewed expansion.
In the 6th century, when Saint Gregory the great sent Saint Augustine of Canterbury to England as a missionary to the Angles, he officially inaugurated this new era.
The new form of Christian mission/Roman federalization, resulted in the name “Christian” being given to the societies that it penetrated, but it was no longer a grass roots/ emergent movement as in the time of Saint Paul. Christianization was now a top down transformation of those societies.[ii]
It was a slow process and it took centuries for the Church to reform those cultures into its own image. The Church was forced to assert it control aggressively and continuously over the worship life of its flock, and the Church never hesitated to use violent coercion, and every other form of persecution to this end.
Barbarian leaders, attracted by the stability of the Christian world, including the access to lucrative markets, education for their children, stable laws turned to Christianity primarily as means to improve the material conditions of their societies and as a means of promoting their own dynastic aspirations.[iii]
By the 10th century, the Church had become the sole arbiter of royal power.
Even though powerful war-lords were able to exercise power in their own right, almost invariably those war-lords sought to have their powers ratified by the Church whose authority it was to hand out royal crowns and other titles including that of emperor.[iv]
Often the only difference between a bandit and a prince was ecclesiastical sanction.