In order to understand the Roman Catholic Church, one must understand its long history. This website explains what the Roman Catholic Church is. Basically, it describes that the Roman Catholic Church is founded by the Lord Jesus Christ and his twelve apostles. When Peter was granted the power to become the first pope, the head of the apostles, he also made precedence of what the Roman Catholic Church should look like. In the present era, the pope embodies Peter, and the pope's cardinals (a type of higher-ranking bishop) and bishops embody the original apostles. Together, the pope and his close circle of bishops represent the unity of the universal, or catholic, church. Whenever there are disputes within the church, the pope has the final word on faith and morals due to the establishment of papal infallibility. The purpose is to make sure that the Church has a common mission, common background, common faith.