Sort of yes and sort of no. Christianity spread through imperialism, and conquest. The reason that Catholicism is the largest denomination of the christian religion is because it spread through the Spanish Portuguese, and Roman empires, which is why South America and most of the world is predominantly Catholic. 

Inevitably, though I think the main reason for the spread was the stability provided by the relative stability of the Roman Empire. Once Constantine signed the Edict of Milan (313 CE) the new religion began to flourish and spread. Obviously it reached some countries sooner than others -- the "twilight" of the Norse gods, for … Read more