Which religious institution banned trade with certain regions controlled by Muslims?

Greek Orthodox
Buddhism
papacy/Catholic Church
Islamic caliphate

The papacy/Catholic Church is the religious institution that banned trade with certain regions controlled by Muslims.

The papacy/Catholic Church banned trade with certain regions controlled by Muslims.

The religious institution that banned trade with certain regions controlled by Muslims was the Catholic Church, specifically under the authority of the papacy.

To arrive at this answer, you can follow these steps:

1. Understand the context: It's important to have some knowledge about the history and interactions between different religious institutions and regions during the medieval period.

2. Examine the given options: Read through the options provided - Greek Orthodox, Buddhism, papacy/Catholic Church, and Islamic caliphate - and consider which institution might have had the authority and influence to implement trade bans.

3. Evaluate the options: Cross out options that are unlikely based on historical knowledge. Buddhism, for example, does not have a central authority that can enact such bans. The Islamic caliphate, on the other hand, actually facilitated trade during the medieval period through the establishment of networks and routes.

4. Consider the Catholic Church: Knowing that the Catholic Church played a significant role during the medieval period, with the pope acting as the highest authority, it becomes plausible for the papacy to have banned trade with certain Muslim-controlled regions.

Hence, the correct answer is the papacy/Catholic Church.