Shia–Sunni relations

Sunni Islam and Shia Islam are the two major denominations of Islam. Their division traces back to a Sunni–Shia schism following the death of the Islamic prophet Muhammad in the year 632. A dispute over succession to Muhammad as a caliph of the Islamic community spread across various parts of the world, which led to the Battle of Jamal and Battle of Siffin. The dispute intensified greatly after the Battle of Karbala, in which Hussein ibn Ali and his household were killed by the ruling Umayyad Caliph Yazid I, and the outcry for revenge divided the early Islamic community.

The present demographic breakdown between the two denominations is difficult to assess and varies by source, but a good approximation is that 85–90% of the world's Muslims are Sunni and 10–15% are Shia, with most Shias belonging to the Twelver tradition and the rest divided between many other groups. Sunnis are a majority in most Muslim communities: in Southeast Asia, China, South Asia, Africa, and most of the Arab world. Shia make up the majority of the citizen population in Iraq, Bahrain, Iran and Azerbaijan, as well as being a politically significant minority in Lebanon, Syria and Yemen. Azerbaijan is predominantly Shia; however, practicing adherents are much fewer.Indonesia has the largest number of Sunni Muslims, while Iran has the largest number of Shia Muslims (Twelver) in the world. Pakistan has the second-largest Sunni as well as the second-largest Shia Muslim (Twelver) population in the world.

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