


Sectarian violence persists to this day from Pakistan to Yemen and is a major element of friction throughout the Middle East and South Asia.

In recent years, Sunni–Shia relations have been increasingly marked by conflict, particularly the Iran–Saudi Arabia proxy conflict.

Although all Muslim groups consider the Quran to be divine, Sunni and Shia have different opinions on hadith. Today, there are differences in religious practice, traditions, and customs, often related to jurisprudence. Shia make up the majority of the citizen population in Iran, Iraq, Bahrain, and Azerbaijan, as well as being a minority in Pakistan, Lebanon, Saudi Arabia, Syria, Yemen, Nigeria, Afghanistan, Chad and Kuwait. Sunnis are a majority in almost all Muslim communities around the world. The present demographic breakdown between the two denominations is difficult to assess and varies by source, with most approximations stating that roughly 90% of the world's Muslims are Sunni and 10% are Shia with about 85% of Shias belonging to the Twelver tradition, and the rest divided between other small groups. This is known today as the Islamic schism. 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 and children of the household of prophet (Ahl al bayt), 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 dispute spread across various parts of the Muslim world, which eventually led to the Battle of Jamal and Battle of Siffin. After the death of 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 Shias, believed that his successor should have been Ali. 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.
