High Quality Content by WIKIPEDIA articles! Christianity in Iran has a long history, dating back to the early years of the faith. It has always been a minority religion, with the majority state religions — Zoroastrianism before the Islamic conquest, Sunni Islam in the Middle Ages and Shia Islam in modern times — though it had a much larger representation in the past than it does today. Christians of Iran have played a significant part in the history of Christian mission. Today, there are at least 600 churches in Iran.