Pope Paschal II was the head of the Roman Catholic Church from 1099 to 1118. He is best known for his efforts to strengthen the authority of the papacy and for his involvement in the Investiture Controversy, a conflict between the church and secular rulers over the appointment of bishops. His papacy coincided with the time of the First Crusade, which aimed to reclaim the Holy Land. During his reign, Paschal II supported the reform of the church and promoted the idea of papal supremacy. He also worked to improve relations with the Byzantine Empire and sought to resolve disputes within the church. His leadership helped shape the future of the papacy and its role in European politics.