What are the factors that contribute to the placement of different people of faith throughout the world

One of the factors that contribute to the placement of different people of faith throughout the world is immigration, people moving from one place to around the world had a huge influence in the place where they were settling. As with Buddhist immigration, that is practically dead where it began in India but was widely spread to China, Japan and Korea.

Other factor is political parties assuming power and imposing new religions on people or forcing by their new policies some groups to move out, as Jewish were forced out of Europe during World War II.

Also missionaries's trips are one factor, as the Christian mission trips to South America, that influenced whole nations, as in Brazil with the visits of Jesuits for catechization of tribes.