How did christianity spread through the roman empire in it's early days? how did it become popular?

During the time of the monks the literacy rate were extremely low, only about 3% could read and or write and most were monks. The monks copied down ancient writings like the Bible and taught the Gospel to other people who had taken the opportunity.

Missionaries spread were people, who probably learned it from the monks, who traveled around to preach the Gospel most later became martyrs.

Martyr refers to the people who are willing to sacrifice their life for a certain cause. In the past, many Christian missionaries become a martyr by defending their religion in the face of torture and execution. As the news of their death spread, they indirectly showed the strength of their belief which ignite other people's will to adopt the religion.

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