How did the Catholic Church impact the politics of the Middle Ages?

As the Church and State were closely tied during the Middle Ages, all authority figures such as kings and queens were duty bound to nurture, promote and reinforce the authority of the church. The belief that kings were sacred because of their office came from and was continuously upheld by the church, encouraging people to blindly obey the dictates of their sovereigns. Rulers understood that it was essential they had the approval of the Church for most of their political moves since disfavor or excommunication could be the kiss of death for a monarchy.