God's love, God's will, the Holy Spirit, and the information of Jesus is (savior) led to the spread of the Christian religion.
Chistian
Migration is cause of spread of religion. As people travel they bring along their religion, and the constitution does not prevent them.
Chistian,US is one of the few coutries is not on the crosshairs of Islams.
This was Rome whose Government was mercilessly killing the followers of Jesus at one time and about a century after it. If anyone who was not a christian in Rome was considered to be an "evil". It bettered the condition of people in Rome. Gladiators were banned after it. Fighting with animals was also banned and many other reforms took place.
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.
The Dutch revolted against Spain because the king was trying to spread the Catholic religion.
Missionaries are the people who help spread a religion.
God.
chistian
It would be helpful if you specified which religion. However, oftentimes, especially with Christianity, persecution caused people to spread out. Also, Christians are commanded to spread the Gospel to the uttermost parts of the earth, and many become missionaries to rural parts of the world.
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.
Islam spread from Arabia.