From Wikipedia, the free encyclopedia - View original article
|This article needs additional citations for verification. (December 2009)|
The major religion in Iraq is Islam, followed by about 97% of Iraqis. The other 3% consist of those following Christianity and other religions. Many cities throughout Iraq have been areas of historical prominence for both Shia and Sunni Muslims including Najaf, Karbala, Baghdad and Samarra.
Iraq's Muslims follow two distinct traditions, Shia and Sunni Islam. According to the Encyclopædia Britannica, Iraq is 97% Muslim: 65% Shia (Arabs, Feyli Kurds, Turkmen, et al.) and 32-37% Sunni (Arabs and Kurds, with Kurds being mostly secular). Iraq is home to many religious sites important for both Shia and Sunni Muslims. Baghdad was a hub of Islamic learning and scholarship for centuries and served as the capital of the Abassids. The city of Karbala has substantial prominence in Shia Islam as a result of the Battle of Karbala, fought on the site of the modern city on October 10, 680. Similarly, Najaf is renowned as the site of the tomb of Alī ibn Abī Tālib (also known as "Imām Alī"), whom the Shia consider to be the righteous caliph and first imām. The city is now a great center of pilgrimage from throughout the Shi'a Islamic world and it is estimated that only Mecca and Medina receive more Muslim pilgrims. The city of Kufa was home to the famed scholar, Abu Hanifah whose school of thought is followed by a sizable number of Sunni Muslims across the globe. Likewise, Samarra is also home to the al-Askari Mosque, containing the mausoleums of the Ali al-Hadi and Hasan al-Askari, the tenth and eleventh Shia Imams, respectively, as well as the shrine of Muhammad al-Mahdi, known as the "Hidden Imam", who is the twelfth and final Imam of the Shia of the Ja'farī Madhhab. This has made it an important pilgrimage centre for Ja'farī Shia Muslims. In addition, some female relatives of the Prophet Mohammad are buried in Samarra, making the city one of the most significant sites of worship for Shia and a venerated location for Sunni Muslims.
Smaller sects of Islam exist in the country, such as the small Shia Shaykhist community concentrated in Basra and Karbala. The Muslim population of Iraq is approximately 60-65 percent Shi'a, 15-20 percent Arab Sunni and 17 percent Kurdish. Iraqi Kurds are mainly secular Sunnis, with a sizeable Shia Feyli population. Most Kurds are located in the northern areas of the country, with most following the Shafi school of Islamic law. With some being members of either the Qadiri or the Naqshbandi Sufi tariqah.
Christianity was brought to Iraq in the first century by the Apostle Thomas, Addai (Thaddaeus) and his pupils Aggagi and Mari. Thomas and Thaddeus belonged to the twelve Apostles. Iraq's Assyrian minority represents roughly 3% of the population (earlier CIA Factbook), mostly living in Northern Iraq, concentrated in the Ninewa and Dahuk governorates. There are no official statistics, and estimates vary greatly. In 1950 Christians numbered 10% of the population of 5.5 million. They were 8% in a population of 16.3 million in 1987 and 1.5 million in 2003. Since the 2003 Iraq war, Iraqi Christians have been relocated to Syria in significant but unknown numbers, but the current CIA Factbook from numbers suggests 0.8% Christians as Iraq's largest religion outside Islam. An ongoing conflict in 2014 due to ISIS makes any population estimate uncertain. However, sources estimate that there are between 200,000 - 300,000. 
Iraqi Christians are divided into three church bodies:
Judaism first came to Iraq under the rule of the Babylonian king Nebuchadnezzar II of Babylon. It was a part of the Babylonian Captivity. After the 6 Day War in Israel, rioting caused the majority of Jews to flee. Fewer than 100 Jews remain in Iraq.
The Yazidis live mostly near Mosul and are made up of ethnic Kurds. Yazidism dates to pre-Islamic times and Mosul is the principal holy site of the Yazid faith. The holiest Yazid shrine is that of Sheikh Adi located at the necropolis of Lalish.
The Mandaean faith has existed in Iraq since the reign of Artabanus V of Parthia according to the Haran Gawaitha (secret wanderings) scroll of secondary Mandaean writ. This would make the Iraqi presence of Mandaeans at least 1,800 years old, making it the third oldest continually professed faith in Iraqi society after Zoroastrianism and Judaism. There are more Mandaeans in Iraq than there are Zoroastrians or Jews combined. In Iraq estimates of around 60,000 have been made. The oldest independent confirmation of Mandaean existence in the region is the Kartir inscription. The Mandaean faith is commonly known as the last surviving Gnostic faith and its adherents believe it to be the oldest faith on Earth, with at least some scholarly support for it being as old if not older than Christianity perhaps even being a major influence in the development of heterodox Jewish circles which eventually led to the formation of Christian beliefs, practices, rituals and theology. John the Baptist or Yahia Yuhanna is considered to have been the final Mandaean prophet and first true Ris'Amma, or Ethnarch, of the Mandaean people. Most Iraqi Mandaeans live near waterways because of the practice of total immersion (or baptism) in flowing water every Sunday. The highest concentrations are in the Mesene province with headquarters in Amarah, Qalat Saleh and Basra. Besides these southern regions bordering Kuzistan in Iran, large numbers of Mandaeans can be found in Baghdad in the Dweller's Quarters, giving them easy access to the Tigris River.
Zoroastrianism first came to Iraq when Babylon was conquered by the Persian Empire. Zoroastrianism in Iraq declined after the fall of the Sassanid Empire and very few, if any, Zoroastrians remain. Only an estimated 40 people in Iraq believe in this faith.