Title: Islam in Iran
Content:  ''' The Muslim conquest of Persia (637&ndash;651) led to the end of the Sasanian Empire and the eventual decline of the Zoroastrian religion in Iran (Persia). Islam has been the official religion of Iran since then, except for a short duration after the Mongol raids and establishment of Ilkhanate. Iran became an Islamic republic after the Islamic Revolution of 1979 which ended the Persian monarchy. Before the Islamic conquest, the Persians had been mainly Zoroastrian; however, there were also large and thriving Christian and Jewish communities, especially in the territories of at that time northwestern, western, and southern Iran, mainly Caucasian Albania, Asōristān, Persian Armenia, and Caucasian Iberia. While a significant number of 
Title: Religion in Iran
Content:  Religion in Iran has been shaped by multiple religions and sects over the course of the country's history. Zoroastrianism was the main religion during the Achaemenid Empire (550–330 BC), the Parthian Empire (247 BC – 224 AD) and the Sasanian Empire (224–651 AD). In 651 AD, the Rashidun Caliphate conquered Persia and spread Islam as the main religion. Sunnism was the predominant form of Islam before the devastating Mongol conquest, but subsequently, Shi'ism became eventually utterly dominant in all of Iran with the advent of the Safavids. The current religious demographics of Iran are disputed. According to the 2011 Iranian census, 99.98% of Iranians believe in Islam, while the rest of 
Title: History of Asia
Content:  The Achaemenid dynasty of the Persian Empire, founded by Cyrus the Great, ruled an area from Greece and Turkey to the Indus River and Central Asia during the 6th to 4th centuries BCE. Persian politics included a tolerance for other cultures, a highly centralized government, and significant infrastructure developments. Later, in Darius the Great's rule, the territories were integrated, a bureaucracy was developed, nobility were assigned military positions, tax collection was carefully organized, and spies were used to ensure the loyalty of regional officials. The primary religion of Persia at this time was Zoroastrianism, developed by the philosopher Zoroaster. It introduced an early form of monotheism to the area. The religion banned animal sacrifice and the use of intoxicants in rituals; and introduced the concept of spiritual salvation through personal moral action, an end time, and both general and Particular judgment with a 
Title: Muslim conquest of Persia
Content:  Abd al-Malik and Umar ibn Abd al-Aziz. There were also large and thriving Christian and Jewish communities, along with smaller numbers of Buddhists and other groups. However, there was a slow but steady movement of the population towards Islam. The nobility and city-dwellers were the first to convert. Islam spread more slowly among the peasantry and the dihqans, or landed gentry. By the late 10th century, the majority of the Persians had become Muslim. Until the 15th century, most Persian Muslims were Sunni Muslims, though with rise of Safavids in early 16th century and their forced conversion of Sunnis lead to rise of Shi'a Muslim faith in Iran.
Title: Eastern Orthodoxy in Iraq
Content:  The early history of Eastern Orthodoxy in the region of Mesopotamia (within the territory of modern-day Iraq) was marked by frequent Byzantine-Sasanian wars, fought between the 5th and 7th century. During much of that period, major part of Mesopotamia was controlled by the Sassanian Empire (Persia). Official Persian religion was Zoroastrianism, while Christianity was occasionally tolerated or persecuted, depending on the current religious or political climate. Attitudes of Persian rulers towards their Christian subjects was affected mainly by current political relations with the Byzantine Empire, seen by Persians as the rivaling power with considerable and worrying influence on Christian communities within Persian borders. Since Byzantine government generally favored Eastern Orthodoxy over 
Title: Religion in the Punjab
Content:  The Persians were the first to use the term Hindu, referring to a vast territory containing much regional variety in belief and practice. Nevertheless, the common concept was the belief in cycles of reincarnation, or sansār, and was the oldest recorded religion in the region. While law books like the Manusmriti codified socio-religious customs and were sanctified by the Hindu religion, such books more generally influenced the formation of broader traditional societal beliefs. The presence of Islam was established through waves or Muslim conquest and rule, and conversions under various empires. Islam was introduced via southern Punjab in the 8th century, becoming the majority population by the 16th century, via conversion. There was also a small Jain community in Punjab by the 16th 
Title: Parsis
Content:  early Muslim conquests. At the time of the Muslim conquest of Persia, the dominant religion of the region was Zoroastrianism, an Iranian religion that also served as the official state religion of the Sassanid Empire. Many notable Iranian figures, such as Babak Khorramdin, actively rebelled against the Rashidun army and later Muslim caliphates for almost 200 years, while the others chose to preserve their religious identities by fleeing from Iran to India during this time. The word Parsi is derived from the Persian language, and literally translates to Persian, effectively identifying the Parsi people as pre-Islamic Zoroastrian ethnic Persians in India and Pakistan. Farsi, a modern word that is used 
Title: Islam in Iran
Content:  also adopted Buddhism in eastern Iran such as Bactria and Sogdia. There was a slow but steady movement of the population toward Islam. When Islam was introduced to Iranians, the nobility and city-dwellers were the first to convert; Islam spread more slowly among the peasantry and the dehqans, or landed gentry. By the 10th century, the majority of Persians had become Muslim. However, the achievements of the previous Persian civilizations were not lost, but were to a great extent absorbed by the new Islamic polity. A poll done by Pew Research Center asking Iranians on the role Islam should play in government showed that 85% of Iranians say that religious figures should 
Title: Persianate society
Content:  Persianate culture flourished for nearly fourteen centuries. It was a mixture of Persian and Islamic cultures that eventually underwent Persification and became the dominant culture of the ruling and elite classes of Greater Iran, Asia Minor, and South Asia. When the peoples of Greater Iran were conquered by Islamic forces in the 7th and 8th centuries, they became part of an empire much larger than any previous one under Persian rule. While the Islamic conquest led to the Arabization of language and culture in the former Byzantine territories, this did not happen in Persia. Rather, the new Islamic culture evolving there was largely based on pre-Islamic Persian traditions of the area, as well as on the Islamic customs that were introduced to the 
Title: Religion in Iraq
Content:  Religion in Iraq dates back to Ancient Mesopotamia, particularly Sumer, Akkad, Assyria and Babylonia between circa 3500 BC and 400 AD, after which they largely gave way to Syriac Christianity and later to Islam. Today, the country is overwhelmingly Muslim, who are split into two distinct sects, Shia and Sunni. According to the CIA World Factbook, 95% to 98% of the population are Muslims. The remainder follow Christianity, Yazidism religious syncretism, Mandaeism, Shabakism, and Yarsanism.

Question: what was the religion in persia before islam?
Answer: the Zoroastrian religion.
Zoroastrian.