The reformation caused the splitting between catholics and protestants. The reformation is also commonly called a schism (and is one of a few schisms that have happened in the history of the christianity).
With the demands of Martin Luther being published, more and more followers found this view of christianity more appealing compared to the one that was present at the time.
This split between protestants and catholics also lead to the Thirty Years' War between 1618 and 1648.
