In the lines of the Apostles, Bishops of particular Churches throughout the world in charge of particular diocese are part of the Church and form the College of Bishops when the College is united as a decision-making body under the leadership of the Pope. The College may exercise power over the Universal Church by coming together in an ecumenical council when the council is recognized by the Pope, the successor of St. Peter. Additionally, "certain bishops are granted special status and position within the Church by being elevated to the College of Cardinals. The primary role of the College of Cardinals is to act as special advisors to the Pope and to come together on the death of a Pope to vote for his successor" ("The Catholic Church Hierarchy," Catholic Pages, 2007). Finally, there is also a counsel, created after Vatican II known as the Synod of Bishops. This formal body acts as advisors to the Pope on church teachings. It was intended as "a move towards the democratization of the Church and the decentralization and diminution of Papal power. It was considered that the Pope, although theoretically still in charge, would not act contrary to the Synod of Bishops" ("The Catholic Church Hierarchy," Catholic Pages, 2007).
It should also be noted that although they are not formally part of the hierarchy, there are Catholics like brothers, monks, nuns, hermits, and friars who have or continue to follow the rules of a specific order that follow a life consecrated to God.
To Western eyes, Islam often seems like a homogeneous 'block,' an idea encouraged by the reference to the 'Islamic world' in the popular press. However, this is a profound misunderstanding of the seismic divisions within the Islamic world, most notably that of Shiite and Sunni Islam. To understand the fractiousness that has characterized Middle Eastern politics, it is essential to understand the historic nature of the split between Sunni and Shiite Islam.
All Muslims obey the five pillars of Islam, which include praying facing Mecca five times daily, fasting from sunup to sundown during the entire holiday month of Ramadan; giving to the poor (much like the Christian or Jewish concept of 'tithing'); making at least one pilgrimage to Mecca during the month of the Hajj if the believer is physically and economically capable of doing so; and belief in the one, unitary God and Mohammed as his Prophet. The Koran is the sacred text for both Shiites and Sunni Muslims. However, over 1,400 years old after the death of the prophet Muhammad, the religion experienced a fundamental fissure in terms of the question of succession, and to how the religion should be structured in terms of its subsequent leadership (Murphy 2007). Some of Mohammed's followers believed that his descendants alone should become caliphs, the leaders of Islamic world. "They were known as the Shiat-Ali or 'partisans of Ali' after the prophet's cousin and son-in-law Ali, whom they favored (Murphy 2008). These adherents became the present-day Shiites. Sunnis, supported Abu Bakr, convert who had married into Muhammad's family, and said that a man's righteousness not his parentage should determine who became caliph. 'Sunni' is derived from the Arab word for 'followers' or 'followers of the prophet' (Murphy 2007).
Today, Sunni Muslims vastly outnumber Shiite Muslims amongst the faithful. "Shiites make up just 15% of the world's Muslims," although they dominate Iran and Iraq (Murphy 2007). Because it is based upon a less centralized system of authority, Sunni Islam was a more 'portable' faith, causing some observers to make an analogy between Protestantism and its faith in the authority of the Bible over Church hierarchies, versus Catholicism's emphasis on institutionalized authority. Shiites venerate descendents of the holy family of the Prophet and Shiites must "observe the advice of an ayatollah on how to follow the law of Islam, or sharia, in the modern context" (Murphy 2007). These ayatollahs might be analogous to rabbis in their authority in that they provide advice that binds a community together, although in Iran ayatollahs have additional authority because of the theocratic nature of the state. Worldwide, the history of defeat and frequent subjugation of Shiite Islam and the greater poverty of many of its adherents as minority communities within a larger Sunni fold has often lead a cult of death and martyrdom within the Shiite tradition. "The major Shiite holidays celebrate the glorious defeats and martyrdoms of Imam Ali and Imam Hussein, Ali's son, as typified by the preeminent Shiite holiday of Ashura, which marks the slaughter of Hussein and his followers outside the Iraqi city of Karbala by a Sunni caliph in 680. In Iraq and Iran, the holiday is marked by elaborate processions of men reenacting their own passion play, many of whom self-flagellate with chains to the beat of drums" (Murphy 2007).
As in Christianity's vision of a final judgment day and some strains of mystical Judaism, there is an especially strong strain of apocalyptic rhetoric in Shiite Islam: "Most Shiites believe that there were twelve legitimate successors to Muhammad as caliph, and that the final imam, now called the Mahdi, disappeared when he was taken up in the arms of God. Many Shiites believe the Mahdi will return to earth one day and play the role of savior. A battle between the forces of good and evil will ensue, ending in a thousand-year reign of peace and the end of the world" (Murphy 2007).
Conclusion comparison between all of these different traditions yields some surprising similarities. All traditions have some place for revered authorities with special insight along with hereditary traditions. For Judaism, a religion whose primary place of worship was destroyed, this authority became predominant in the persona of the rabbis, although some communities such as the Hassidim created their own hereditary tradition parallel to the now largely irrelevant priestly, hereditary classes in most of Orthodox Judaism. Catholicism, a religion that venerates chastity, creates a hereditary tradition through apostolic succession instead, venerating St. Peter's spiritual descendants, rather than physical descendants -- and the spiritual legacy of Rome and its importance in the church. And finally, while Shiite Islam venerates the descendants of the Prophet Mohammed, it also has a place for the advice of ayatollahs. All traditions make a place for wisdom and tradition, innovation and respect for legacy through these various structures.
The Catholic Church Hierarchy." Catholic Pages. 2007. December 7, 2008. http://www.catholic-pages.com/church/hierarchy.asp
History and Development of the Papacy." Religion Facts. 2008