The Medieval Catholic Church was the central authority in Western Europe and taught that people were inherently sinful and dependent on God's grace to reach heaven. People participated in sacraments like baptism, communion, and confession that were administered by the Church. While Christianity could be complex, monks and nuns helped spread the religion through missionary work, teaching literacy, and operating hospitals. The Church held significant political and social power through the 1100s when calls for reform began regarding issues like corruption among clergy.