More than 90% of the population of Azerbaijan is Muslim. (Estimates include 96.9% Muslim, 93.4% (Berkley Center, 2012), 99.2% (Pew Research Center, 2009).) The rest of the population adheres to other faiths or are non-religious, although they are not officially represented. Among the Muslim majority, religious observance varies and Muslim identity tends to be based more on culture and ethnicity rather than religion. The Muslim population is approximately 60-65% Shi'a and 35-40% Sunni; differences traditionally have not been defined sharply. Most Shias are adherents of orthodox Ithna Ashari school of Shi'a Islam. Other traditional religions or beliefs that are followed by many in the country are the Hanafi school of Sunni Islam. Traditionally villages around Baku and Lenkoran region are considered stronghold of Shi'ism. In some northern regions, populated by Sunni Dagestani (Lezghian) people, the Salafi movement gained some following. Folk Islam is widely practiced. According to a 2010 Gallup Poll found 49% of Azerbaijanis answering no to the question "Is religion an important part of your daily life?", one of the highest rates among any Muslim-majority country. A 1998 poll estimated the proportion of ardent believers in Azerbaijan at only 20 percent. History Islam arrived in Azerbaijan with Arabs in the seventh century, gradually supplanting Christianity and pagan cults. 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 a portion of people remained Sunni. The population of what is nowadays Iran and what is nowadays Azerbaijan were converted to Shia Islam at the same moment in history. 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 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. Russian Empire and Soviet Union In 1806, Azerbaijan became occupied by the Russian Empire as the latter invaded Qajar Iran during the Russo-Persian War (1804-1813). In the aftermath, Iran was