Missionaries are the people who help spread a religion.
By the time this people were called Franks they were Christians.
Jewish
Religion over the years has had the tolerance stand still, people are still in arguments about religion, but people do still go church, though since the second world war religion has spread rapidly.
Constantine helped spread Christianity throughout the Roman Empire. He issued the Edict of Milan in 313, which granted religious tolerance to Christians and allowed them to practice their faith openly. Constantine's conversion to Christianity and support of the religion played a significant role in its growth and development.
He was raised Catholic - unsure of his current faith.
Islam spread from Arabia.
If we take time as a measure of the spread of religion,then since its establishment ,Islam is the religion which spread or still spreading rapidly in Asia followed by Christianity.
The sufies are soft spoken kind hearted people. They spread Islam by being kind and loving to the non-believers.
It spread by Christian missionaries looking for a new place to spread their religion
Migration is cause of spread of religion. As people travel they bring along their religion, and the constitution does not prevent them.
Islam was the religion that spread from the Arabian Peninsula to Africa.