Lay Investiture is too broad a topic to cover in a quick answer site like WikiAnswers, below are links to articles about it in WikiPedia and the Catholic Encyclopedia.
Both of these parties wanted to be in control. They thought they should be the head and didn't like each other.
The appointment of church officials by kings and nobles rather than by the pope
The appointment of church officials by kings and nobles rather than by church officials apex
Emperors and kings disagreed with the Popes over who should appoint bishops. The disagreement lead to the Investiture controversy.
THey gained more power and got to have some control of the church. I am working on the same one
Rivalry between french and english kings.
Rivalry between french and english kings.
Pope Gregory VII issued the Dictatus Papae in 1075, which outlined the powers of the pope and asserted papal supremacy over secular rulers. He forbade kings from exercising authority over church appointments and insisted that only the pope had the power to appoint bishops and invest them with spiritual authority. This conflict with secular rulers, particularly with Emperor Henry IV, contributed to the Investiture Controversy, a significant power struggle between church and state during the Middle Ages.
Through lay investiture, kings gained significant control over the appointment of bishops and abbots, effectively increasing their influence over the Church and its resources. This practice allowed monarchs to ensure loyalty from church leaders, who often held substantial power and land, thereby reinforcing the king's authority and stabilizing his rule. Additionally, by appointing clergy, kings could use religious institutions to support their political agendas and consolidate their power within the realm.
Lay investiture was most favored by monarchs and secular rulers who sought to strengthen their authority and control over the church within their territories. They believed that by appointing bishops and other church officials, they could ensure loyalty and align religious influence with their political power. This practice often led to significant conflicts with the papacy, particularly during the Investiture Controversy in the 11th and 12th centuries. Kings like Henry IV of Germany were prominent proponents of lay investiture, arguing it was essential for maintaining order and governance.
cause they are kings?
Henry wanted the right to name new bishops in his kingdom. Gregory stated that only the pope could elevate bishops. It became known as the Lay Investiture Controversy.