Congressional Research Service
The Library of Congress
CRS Report for Congress
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Order Code RS21745
February 23, 2004
Islam: Sunnis and Shiites
Analyst in Middle East Religions and Cultures
Foreign Affairs, Defense, and Trade Division
The majority of the world’s Muslim population follows the Sunni branch of Islam,
and approximately 10-15% of all Muslims follow the Shiite (Shi‘ite, Shi‘a, Shia)
Shiite populations live in a number of countries, but they constitute a majority
in Iran, Iraq, Bahrain, and Azerbaijan.
There are also significant Shiite populations in
Afghanistan, Kuwait, Lebanon, Pakistan, Saudi Arabia, Syria, and Yemen.
Shiites share most basic religious tenets.
However, their differences sometimes have
served as the basis for religious intolerance, political infighting, and violent
This report includes a historical background of the Sunni-Shiite split
and the differences in religious beliefs and practices between and within each Islamic
sect as well as their similarities.
This report will not be updated.
Related CRS products
include CRS Report RS21432 and CRS Report RS21695.
The differences between the Sunni and Shiite Islamic sects are rooted in
disagreements over the succession to the Prophet Muhammad, who died in 632 AD, and
over the nature of political leadership in the Muslim community.
The historic debate
centered on whether to award leadership to a qualified and pious individual who would
lead by following the customs of the Prophet or to preserve the leadership exclusively
through the Prophet’s bloodline. The question was settled initially when community
leaders elected a close companion of the Prophet’s named Abu Bakr to become the first
Caliph (Arabic for “successor”).
Although most Muslims accepted this decision, some
supported the candidacy of Ali ibn Abi Talib, the Prophet’s cousin and son-in-law,
husband of the Prophet’s daughter Fatima. Ali had played a prominent role during the
Prophet’s lifetime, but he lacked seniority within the Arabian tribal system and was
bypassed as the immediate successor.
This situation was unacceptable to some of Ali’s followers who considered Abu
Bakr and the two succeeding caliphs (Umar and Uthman) to be illegitimate. Ali’s
followers believed that the Prophet Muhammad himself had named Ali as successor and
that the status quo was a violation of divine order. A few of Ali’s partisans orchestrated
the murder of the third Caliph Uthman in 656 AD, and Ali was named Caliph. Ali, in