Why did Christianity have trouble fitting in with the Roman Empire?

Because the covenant of monotheism prohibited Christians from participating in the imperial cults, many Romans had a difficult time accepting them. The imperial cults were often considered to be measures of loyalty to the state. Earlier concessions had been granted to Jewish sects, however, who were also monotheist, but these sects had a longer-lasting role within the empire and were not seen as threatening to it. Christianity offered everyone, regardless of social status, a place in the world and the afterlife, for maintenance of their covenant. But because Christianity was also practiced privately, it conflicted with the Roman tendency to practice religion in public and in open spaces; private meetings were seen as places where conspiracies might happen. Finally, in part because of the private nature of the religious practices, many non-Christians had great misconceptions regarding some of the rites practiced, accusing Christians of cannibalism and incest. All of these factors made it difficult for Christianity to fit into the Roman Empire.