mont-, mount-

1. Situated beyond the mountains.
2. Relating to people or regions lying beyond the mountains, especially the Alps.
3. Coming from or lying beyond mountains; especially, beyond the Alps as viewed from ancient Rome.
4. Supporting the power and authority of the pope within the Roman Catholic Church.

A reference to the advocacy of the supremacy of the papacy and the papal system, in opposition to those favoring national churches and the authority of church councils.