While Islam strongly dominates the Iraqi society, there are several religions surviving in the mountains and in the capital. Baghdad has centuries long rtaditions as a cosmopolitan city, often offering refuge for groups fleeing from far away. Also, the geography of the mountains has allowed smaller groups to find shelter from zealous rulers.
Iraq has a prominent place in Islamic history, both being the centre of the Muslim world for 500 years, from the middle of the 8th until the middle of the 13th century, as well as being having the most of the religious sites for Shi'ism.
Centuries of tolerance is largely lost today, many minorities complain about hardship both on the individual level as well as in relation to freedom to worship.
There are two branches of Islam present in Iraq, Twelver Shi'i and Sunni. Similar to Iran and Bahrain, Iraq has a Shi'i majority. This majority has, however, not been able to exercise much political power until the 2000's, with the removal of President Saddam Hussein and his Sunni elite.
Modern Iraq has a strong affinity between religious adherence and politics.
Twelver Shi'i Islam is the largest religious group of Iraq, and this even corresponds well to the religious geography of the country. Iraq is home to several of the most important sites for Shi'ism. Karbala and Najaf are the two most important sites for Shi'ism. Karbala is where the decisive battle that separated Sunnis and Shi'is from the late 7th century, also here buried the 3rd imam, Husayn. At Najaf, the most prominent Shi'i figure is buried, Ali, the 1st imam, but also the 4th caliph of a united Islam. Altogether, 7 of the 11 imam tombs in Twelver Shi'ism are located in Iraq, the two more each in Baghdad (Musa al-Kazim and Muhammad at-Taqi) and Samarra (Ali al-Hadi and Hassan al-Askari). There is no tomb of the 12th imam, who Shi'is claim only went into occultation, but there is a shrine to his honour at Samarra.
Iraq is a major destination for Shi'i pilgrimage.
Shi'ism gained ground over several centuries, through the conversion of entire tribes, right up until the 20th century. Shi'ism was attractive both as a mean of exercising political autonomy during the time when Iraq was part of the Ottoman Empire, but also, the immediate religious sites of Shi'ism made this branch appealing to many Iraqis.
In independent Iraq, the Shi'is were marginalized from main politics already during the 1960's. Ever since, the relation between the Sunni-dominated central Iraq and the Shi'i-dominate south has been tense. The Shi'is tried to cut themselves loose from Baghdad after the Gulf War of 1991, then being heavily punished by Saddam until the war of 2003. Shi'is now have a strong position in society. Shi'is have have been able to take much political power in Iraq since the US/British-Iraq War began 2003, but little suggest that there will a split of the country from a Shi'i initiative.
With Shi'is as the majority, Sunnis as a great minority that has been the dominating elite for the last decades, there are strong divisions between the two groups.
At Kufa, is the tomb of Abu Hanifa, one of the most prominent scholars for the development of Sharia, Muslim law.
Christianity has deep roots in Iraq. Estimates on the size of the communities are uncertain, partly because of the migrations following the US/British-Iraq War began 2003.
In 1950, the Christians constituted up to 10% of the Iraqi population.
Iraqi Christians have their own church traditions, representing some of the oldest traditions in Christianity. These churches are known under several names: the Nestorians are also called Eastern Assyrians; the Syriac Catholics are also called Jacobites; the Chaldean Catholics are also called Chaldean Assyrians.
Yazidis with about 500,000 members.
The Yazidi religion belongs to the northern regions of Iraq, being practiced among the Kurds. Their main region is around Mosul. The Yazidis are largely isolated from their neighbours.
Shabak religion is little described, and seems to be in close relation with Yazidism.
Of the Mandean religion, which counted 30,000 adherents in Iraq before the US/British-Iraq War started in 2003, many have fled Iraq, as they were a group that benefitted greatly from the protection of the regime of Saddam Hussein.
Mandaeism has been present in Iraq at least 1,800 years.
Mandeans form several small communities, the largest in Baghad.
The history of Judaism in Iraq goes deep back in history, to the era of Babylonia in the 6th century BCE, and King Nebuchadnezzar 2. Jews have in modern times emigrated in large numbers, in particular to Israel. The size of the remaining community is uncertain, estimates range between 100 and 2,500, all live in Baghdad.