How did the catholic church expanded in the middle ages?

During the high Middle Ages, the Roman Catholic Church became organized into an elaborate hierarchy with the pope as the head in western Europe. He establish supreme power. Many innovations took place in the creative arts during the high Middle Ages. Literacy was no longer merely requirement among the clergy.

Europe was unified under the idea that people must convert to Christianity. The church is soon governmental duties and create a church hierarchy. The pope had the same power the Roman emperor once had