The role of religion and church was very influential during The Middle Ages and the Renaissance. They possessed a great deal of power that couldn't be taken away by any ruler. In fact, the church was a counter to kings who wanted absolute power. Any king who wished to rule must have the church on his side. Opposing the church would lead to excommunication. Today this doesn't sound like much, but at the time, excommunication translated to the downfall of one's kingdom. .
The Middle Ages were a time in which everything was controlled by oaths. So for a king to oppose to the church meant that he was breaking the oath of allegiance he had with God. This resulted on the pope excommunicating the king. Now, everyone from the king's subjects to his enemies could be freed from those oaths, and all of the allegiance with that particular king could be cancelled. This means that anyone could rise up in revolt or invade, without fear of condemnation by the church. Also, any subjects of the king who opposed his views could switch sides without being accused of treason. .
The church also played an important role in government. Being allied with the king, church leaders such as bishops and archbishops sat on the king's council and played influential roles in society. These important roles granted them power and wealth. But not anyone was appointed to these positions. Bishops and archbishops were sons of wealthy respectable people who had the money to bless their children with an education. .
Education was another factor controlled by the church. During the Renaissances time the church was in charge of providing those worthy enough with an education. In fact, the church influenced all the new ideals that constructed the renaissances such as, humanism, art, science, self-awareness, trivium, quadrivium, and religion. For example, the appreciation for art was resuscitated, but most art works were commissioned by or in dedication to the church.