Who had more power in medieval Europe: popes or kings. Why?

The Pope was given the victory and the power at the time, however, it was short lived and eventually was one of the reasons that led to the future collapse of the Middle Ages. Why? Because he was able to decide what the church would teach and more importantly during this time he was able to determine who was an enemy of the church. If the Pope deemed someone as a foe of the church, he was able to Excommunicate those who opposed his teachings. With these changes, the Pope was able to gain a vast amount of political power as well as fame and fortune, due to his followers, and ultimately challenge the King for supreme power throughout the land. Something like that