Islam is the state religion of Bahrain, representing more than 80% of the population. The non-Muslims are almost entirely non-citizens, and among immigrants, many are Muslims. Religious freedom is secured by the constitution, other faiths may worship publicly and establish designated places of worship.
Bahrain's religion history has a few noticeable events, in particular during the time when it was a stronghold for the Qarmantian sect, and the Bahrainis in 930 sacked Mecca and Madina, desecrated the Zamzam with dead bodies and stealing the Black Stone with them home, to keep it for 20 years.
Bahrain has a very conflicted relationship between its two branches of Islam; Sunni and Shi'i. Shi'i is the religion of the majority of the population, Sunni is the religion of the elite, both politically and economically.
Bahraini authorities have in recent decades promoted immigration from countries like India, Philippines and Sri Lanka, causing a fall in the relative size of the Muslim community.
The Shi'is of Bahrain may be one group in terms of religion, but is divided into two groups with distinct identities. The larger is of Arab descent, the Baharna, who have very little social interaction with those of Iranian descent, the Ajam.
Although most Shi'is live in cities today, their original lifestyle is that of the small village, forming communities called ma'atam, where most important events of life are centered, and to which the Shi'is owe their allegiance.
Shi'is of Bahrain have limited opportunities in the public sector, and are even more excluded in the military, where no Shi'i hold important positions, even if Shi'is serve as normal soldiers. First in 2002 did the government allow the establishment of Shi'i schools.
Motived both by economic inequality and inspiration of the Iranian revolution, the Shi'is emerged as a main political challenge for the Sunni elite during the 1980's. Today, much of this has been curtailed with effective government suppression.
The Sunnis are living in the cities, where they often make up the majority. Sunnis are mainly of the Shafi'i and Maliki branches (madhhab) of law and theology (Sharia), the ruling family belongs to Maliki. Sunni immigrants may well belong to other madhhabs.
The Sunnis is the political and economic elite of Bahrain, being loyal through descent and history to the ruling family. The Sunnis immigrated to Bahrain mainly 200 years ago from Najd, following the takeover by the Khalifa family. A part of their group are of African descent, originally slaves.
There are reports of Ibadis in Bahrain, possibly immigrants from Oman. Their number is not known, but is for certain low.
Christians of Bahrain are entirely of foreign backgrounds, individuals with no opportunity of ever gaining citizenship, hence the Christian presence in the state is only temporary.
The situation for Hinduism in Bahrain is similar to that of Christianity: all of foreign backgrounds and only temporary.
The Baha'is of Bahrain belong to the Persian community.