Of the two main groups within Islam, Sunni Muslims compose 85–90 percent of all adherents and Shiite Muslims about 10–15 percent. In the late twentieth century, the Sunni made up the majority of Muslims in all nations except Iran, Iraq, Bahrain, and perhaps Yemen. All told, they numbered nearly 1 billion. Sunni Muslims view themselves as the traditional, mainstream, pragmatic branch of Islam; in fact, they became known as the orthodox element in Islam. This claim, however, is in dispute, since all orientations in Islam are a result of the common Islamic origin.

Religious and Political Differences

In early Islamic history, Shiite Muslims were the more political of the two groups. When problems arose over the rightful successors to Muhammad, the Sunni said the first four caliphs were Muhammad's rightful successors, whereas the opposing minority, the Shiites, believed that Muslim leadership belonged to Muhammad's son-in-law, Ali, and then to his descendants. This disagreement led to continuous internal wars that proved to be largely unsuccessful from Ali's point of view. However, Ali's status was eventually recognized and he became a major hero of Sunni Islam.

In contrast to the Shiites, who believed that the leadership of Islam was determined by divine order or inspiration, the Sunni regarded leadership as the result of the prevailing Muslim political realities. Historically, the leadership was in the hands of the foremost families of Mecca. For the Sunni, balance between spiritual and political authority afforded both the correct exercise of religious order and practical maintenance of the Muslim world.

Sunni orthodoxy placed strong emphasis on the majority view of the community. Over the years, this perspective provided them the opportunity to include matters that were outside the root teaching of the Qur'an. Thus, the Sunni have earned the reputation of being religiously and culturally diverse.

The religious and political differences between Sunni Islam and Shia Islam have been fraught with enmity and dissension throughout history. Today, Iran is the bastion of Shia Islam — its state religion — and the majority of Iranians are Shiites. Even so, people in Iran do practice other religions, such as Judaism, Christianity, and even Zoroastrianism, an ancient faith that predates Judaism. Shia adherents also live in Syria, East Africa, India, and Pakistan. Overall, Shiites comprise somewhere in the region of 80 million people, or a tenth of all Muslims.

Shiites maintain that only those in the bloodline of Muhammad are the legitimate heirs of Islam. Shia Islam is often called “twelver” because Iranians generally recognized only twelve imams or supreme religious leaders following the death of Muhammad. The twelfth of these is Mardi, the socalled hidden imam, who is still alive in some celestial state. The ayatollahs, highly respected scholars and teachers of Shia Islam, stand in for Mardi as they interpret the words of Muhammad.

Religious Practices

The religious practices of the Shiites are different from those of the Sunni. For devout Shiites, a pilgrimage to Mecca is the most important religious practice, but they also visit the tombs of the eleven earthly imams, and Iranians frequently cross the boarder into Iraq to visit the tomb of Ali.

In the twentieth century, Shiites became a major political force in Iran, where they deposed a secularist monarchy, and in Lebanon, where they led resistance to Israeli occupation in the south during the 1980s and 1990s.

The Shiites, from a western point of view, would probably be considered the more conservative of the two main factions in Islam. Their doctrine has always firmly revolved around the Qur'an, and in modern times, they have become the chief voice of militant Islamic fundamentalism.