Approximately 93 percent of the population of Azerbaijan is nominally Muslim. The rest of the population adheres to other faiths or consists of atheists, although they are not officially represented. Among the Muslim majority, religious observance is relatively low and Muslim identity tends to be based more on culture and ethnicity rather than religion; however, imams reported increased attendance at mosques during 2003. The Muslim population is approximately 70 percent Shi'a and 30 percent Sunni; differences traditionally have not been defined sharply. Most Shias are adherents of orthodox Ith'na Ashari school of Twelver Shia. Other traditional religions or beliefs that are followed by many in the country are the orthodox Sunni Islam, the Armenian Apostolic Church (in Karabakh), the Russian Orthodox Church, and various other Christian sects. Traditionally villages around Baku and Lenkoran region are considered stronghold of Shi'ism, and in some northern regions, populated by Sunni Dagestani people, Salafi sect gained some following. Folk Islam is widely practiced, but organized Sufi movement is absent.
There are fairly sizeable expatriate Christian and Muslim communities in the capital city of Baku; authorities generally permit these groups to worship freely.
Islam arrived in Azerbaijan with Arabs in the seventh century, gradually supplanting Zoroastrianism and Azerbaijani pagan cults. In the seventh and eighth centuries, many Zoroastrians fled Muslim persecution and moved to India, where they became known as Parsis. Until Soviet Bolsheviks ended the practice, Zoroastrian pilgrims from India and Iran traveled to Azerbaijan to worship at sacred sites, including the Surakhany Temple on the Apsheron Peninsula near Baku.
In the sixteenth century, the first shah of the Safavid Dynasty, Ismail I (r. 1486-1524), established Shi'a Islam as the state religion, although large numbers of Azerbaijanis remained Sunni. The Safavid court was subject to both Turkic (Sunni) and Iranian (Shi'a) influences, however, which reinforced the dual nature of Azerbaijani religion and culture in that period. As elsewhere in the Muslim world, the two branches of Islam came into conflict in Azerbaijan. Enforcement of Shi'a Islam as the state religion brought contention between the Safavid rulers of Azerbaijan and the ruling Sunnis of the neighboring Ottoman Empire.
In the nineteenth century, many Sunni Muslims emigrated from Russian-controlled Azerbaijan because of Russia's series of wars with their coreligionists in the Ottoman Empire. Thus, by the late nineteenth century, the Shi'a population was in the majority in Russian Azerbaijan. Antagonism between the Sunnis and the Shi'a diminished in the late nineteenth century as Azerbaijani nationalism began to emphasize a common Turkic heritage and opposition to Iranian religious influences.
There is also a small Jewish community in Azerbaijan. There are three sinagogues in Baku and a few in the provinces. Sheikh-ul-Islam Allahshukur Pashazade (head of Azeri Shi'a) has donated USD 40,000 for construction of Jewish House in Baku in 2000.
In 1806, Azerbaijan was conquered by the Russians. In 1918, Azerbaijan declared independence from Russia, but was incorporated into the Soviet Union in 1920.
Before Soviet power was established, about 2,000 mosques were active in Azerbaijan. Most mosques were closed in the 1930s, then some were allowed to reopen during World War II. The Soviet rule promoted an Azerbaijani national consciousness as a substitute for identification with the world Islamic community.
In the 1980s only two large and five smaller mosques held services in Baku, and only eleven others were operating in the rest of the country. Supplementing the officially sanctioned mosques were thousands of private houses of prayer and many secret Islamic sects.
Azerbaijanis believed they suffered greater repression than their South Caucasian neighbors, Armenia and Georgia, because of their identification with the world of Islam.
Gradually, during the Soviet imperial twilight, signs of religious reawakening not only multiplied but surfaced into the open. According to Soviet sources, during the late 1970s around 1,000 clandestine houses of prayer were in use, and some 300 places of pilgrimage were identifiable. This growth proved the prelude to the public openings of hundreds of mosques in the following decade.
During World War II, Soviet authorities established the Muslim Spiritual Board of Transcaucasia in Baku as the governing body of Islam in the Caucasus, in effect reviving the nineteenth century tsarist Muslim Ecclesiastical Board. During the tenures of Leonid I. Brezhnev and Mikhail S. Gorbachev, Moscow encouraged Muslim religious leaders in Azerbaijan to visit and host foreign Muslim leaders, with the goal of advertising the freedom of religion and superior living conditions reportedly enjoyed by Muslims under Soviet communism.
Beginning in the late Gorbachev period, and especially after independence, the number of mosques rose dramatically. Many were built with the support of other Islamic countries, such as Iran, Oman, and Saudi Arabia, which also contributed Qur'ans and religious instructors to the new Muslim states. A Muslim seminary has also been established since 1991. As in the other former Soviet Muslim republics, religious observances in Azerbaijan do not follow all the traditional precepts of Islam. For example, drinking wine is permitted, and women are not veiled or segregated.
After independence, the laws regarding religion are quite clear. In Article 6 of the constitution, Azerbaijan is declared a secular state. This point is driven home in Article 19 with the statement of the separation of religion and state and the equality of all religions before the law as well as the secular character of the state educational system.
Secular politicians in Azerbaijan have raised concerns about the rise of political Islam, but others argue that Islam in Azerbaijan is a multifaceted phenomenon. Islam plays only a very limited role in the political sphere and only a small part of the population supports the idea of establishing an Islamic order. This is due to the long tradition of secularism in Azerbaijan and to the fact that the nationalistic movement is secular in character, even when fighting against its rival - Islamism. Yet, according to some analysts, on the longer run, if the politicians do not manage to improve the conditions of life of the vast majority of the people, the population may express its discontent through political Islam.