How did christianity spread through western and central europe during the early middle ages?
missionaries traveled across the continent, preaching the gospels.
the gospels were translated into latin, the language peasants used.
the benedictine rule forced everyone to pay a tithe to support new churches,
monasteries provided education and care for the poor.

Christianity continued to spread because of many missionaries going out and Spreading the word of God. One other reason would have to be the spread of Catholicism which was Christianity but, later changed because of the Romans. This is my basic Knowledge but, I'm not sure if this is going to help but, here you go.

Explanation:

Missionaries traveled across the continent, preaching the Gospels.

it was justfied as english were being brutal to the colonist and they needed to be stopped therfor causing a war but the moral over that is yes it was justifed