The origin of
Shia–Sunni relations can be traced back to a dispute over the
succession to the
Islamic prophet Muhammad as a
caliph of the
Islamic community. After the death of the
Islamic prophet Muhammad in 632, a group of Muslims, who would come to be known as the Sunnis, believed that Muhammad's successor should be
Abu Bakr whereas a second group of Muslims, who would come to be known as the Shia, believed that his successor should have been
Ali. This dispute spread across various parts of the Muslim world, which eventually led to the
Battle of Jamal and
Battle of Siffin.
Sectarianism based on this historic dispute intensified greatly after the
Battle of Karbala, in which
Husayn ibn Ali and some of his close partisans, including members of his household, were killed by the ruling Umayyad Caliph
Yazid I, and the outcry for revenge divided the early Islamic community, albeit disproportionately, into two groups, the Sunni and the Shia. This is known today as the
Islamic schism.
[1]
The present demographic breakdown between the two denominations is difficult to assess and varies by source, but a good approximation is that 90% of
the world's Muslims are
Sunni and 10% are
Shia, with most Shias belonging to the
Twelver tradition and the rest divided between many other groups.
[2] Sunnis are a majority in almost all Muslim communities around the world. Shia make up the majority of the citizen population in
Iran,
Iraq,
Bahrain, and
Azerbaijan, as well as being a small minority in
Pakistan,
Lebanon,
Saudi Arabia,
Syria,
Yemen,
Nigeria,
Afghanistan,
Chad and
Kuwait.
[13][14]
Today, there are differences in religious practice, traditions, and customs, often related to
jurisprudence. Although all Muslim groups consider the
Quran to be divine, Sunni and Shia have different opinions on
hadith.
In recent years, Sunni–Shia relations have been increasingly marked by conflict,
[15] particularly the
Iran–Saudi Arabia proxy conflict.
Sectarian violence persists to this day from Pakistan to
Yemen and is a major element of friction throughout the
Middle East and
South Asia.
[16][17] Tensions between communities have intensified during power struggles, such as the
Bahraini uprising, the
Iraqi Civil War, the
Syrian Civil War, the
War in Iraq (2013–2017),
[18][19][20] the formation of the self-styled
Islamic State of Iraq and Syria that has launched a
genocide against Shias.