In the 10th and 11th centuries, the church had been experiencing a practice called lay investiture. Lay investiture was the practice of churchmen being appointed by laymen (people not in the church). Many kings and nobles appointed priests, bishops, and in some cases, even popes to office. Many bishops became vassals of the lord who appointed him and thus had to serve him. In this period many of the popes were appointed by the Holy Roman Emperors, but they didn’t always turn out so well. As a result the church deteriorated and abandoned many of it’s old practices. The church practiced were simony and clerical marriage, both in opposition to it’s former practices.
Because of all of the problems in the church, Pope Leo IX began instituting reforms in the church. He instituted councils to deal with simony and clerical marriage, and institutes the authority of the pope. He also urged laymen to choose better people. This was called “Moderate reform”.
The church, strengthened by the reforms of Leo IX, moved into a period of Radical reform under Pope Nicholas II. The participants in this reform did not think that laymen should be in charge of appointing church leaders in the first place. They said that the king was a layman, just like everyone else, and that likewise he should not appoint people to positions of authority in the church. They also urged the common people to go on strike against the churchmen who supported many of the things that the reform was trying to eradicate. Nicholas made the rule that the College of Cardinals should choose the popes. This practice continues to this day.
When Gregory VII became the pope, he established radical reform in the church even more. But, many of his reform decrees were not observed. The cause, he discovered, was that the people under him were not appointed by him and thus would not listen to him. Also, Gregory could not appoint his own people into office. So, he strove to take back much of the pope’s power and fought against lay investiture.
But, many feudal monarchs depended on churchmen to assist in the administration of their realms. They did not like the reforms that Gregory was instituting and at times resisted it. The situation was the most serious in the Holy Roman Empire. because of these reforms great showdown began between the Holy Roman emperor, Henry IV, and Gregory.
In 1075, Gregory held a council. The council declared that clerics invested by laymen were deposed and laymen who invested were excommunicated. Henry, though, needed bishops to offset the power of his nobles under him.
Things really got bad when a disagreement over the election of the bishop of Milan surfaced. Henry appointed his choices for the bishop of Milan and other places, but Gregory demanded that he cease. Henry would not, so Gregory excommunicated him. Henry, although, didn’t mind until his nobles rebelled against him. Eventually, Henry was forced to submit due to the rebellion. He met with Henry at Canossa, the Pope’s winter residence, and Gregory lifted his excommunication.
But, after Henry crushed his rebellious nobles, he went right on back to resisting the pope. Three years after his first excommunication, Gregory excommunicated Henry again. But this time around, Henry drove Gregory into exile. Gregory died in exile in 1085. The lay investiture issues were resolved in the Concordat of Worms in 1122.
In this conflict, much of Western liberty was at stake in this conflict. If either of these two powers came into absolute authority, then a tyranny might have been established. Both powers needed the support of the people and issued out liberties to them, making liberty stronger in the west.
During this period, the system of Christendom was predominant. Christendom was an international society based on the unity of religion in Western Europe. As a result, monasteries sent their monks from one country to another without problem, and Bishops and abbots governed places far from their birth. Nationality had nothing to do with choosing a superior among the Cisterian monasteries, as well as acceptance as a university professor in Medieval universities. Artists and craftsmen from different places would work in other places in Europe without problem. The church acted as peacemakers between warring parties, and sanctions by the Pope such as excommunication and the Interdict were feared.