For trade in the middle ages--what corporation had the most power and why

During the Middle Ages, the Roman Catholic Church was the single most powerful organization in Western Europe. There were many reasons for its power. First, people during the Middle Ages were very religious. They believed that the Roman Catholic Church represented God on Earth and held the power to send a person to Heaven or Hell. In addition, many nobles left land to the Church when they died hoping to gain entry into heaven. Therefore, the Church became Western Europe’s largest landowner. Church wealth also increased through tithes or church taxes which all Catholics were required to pay. Finally, the Church was the main center of learning. Church officials were usually the only people who could read and write. Rulers often relied on Church officials, since they were the most educated people during the Middle Ages.