Zoroastrianism was the national faith of Iran for more than a millennium before the Arab conquest. It has had an immense influence on Iranian philosophy, culture and art after the people of Iran converted to Islam.
Today of the 98% of Muslims living in Iran, around 89% are Shi’a and only around 9% are Sunni.This is quite the opposite trend of the percentage distribution of Shi’a to Sunni Islam followers in the rest of the Muslim population from state to state (primarily in the Middle East) and throughout the rest of the world.
Followers of the Baha'i faith are scattered throughout small communities in Iran. Most of the Baha'i are of Persian descent, although there seem to be many among the Azerbaijani and Kurdish people.
Followers of the Christian faith comprise around 250,000 Armenians, around 32,000 Assyrians, and a small number of Roman Catholic, Anglican, and Protestant Iranians that have been converted by missionaries in earlier centuries. Thus, Christians that live in Iran are primarily descendants of indigenous Christians that were converted during the 19th and 20th centuries. Judaism is an officially recognized faith in Iran. However, under Ayatollah Khomeini and his successor, like other religious minorities they are being suppressed and prosecuted.