What was the difference between christianity and other religions?

How did christianity gain so many followers? We all know what happened after the roman empire embraced it as the official religion, but my question concerns what happened before that.Im certain that it wasn't the only religion, so im curious about how did christianity stand out among all the other religions. ------

Christ was the difference.He preached tolerance and love of your fellow man. Completely different that the previous"will of the gods"that was going on before it. ------