What factors enabled Christianity to spread within the Roman Empire?

Great
question. Here are a few points to consider:

1. The most important factor for
the growth of Christianity was that it wanted to grow. This factor might seem small, but this
makes all the difference. Most religions in the Roman world did not seek out converts. The
followers Epicurus and the Jews might be the only exceptions. Christianity, on the other hand,
wanted to grow. Just look at Paul's missionary journeys.

2. Because Rome had
such a great empire in terms of travel, any religion that wanted to spread could. In other
words, Christianity came at the right time.

3. Christianity also had
a...