Zoroastrianism is an ancient faith, founded by Zarathustra around 600 BC. Zoroastrians believe in One God, Ahura Mazda, and the enemy of this One God, Angra Mainyu, who is constantly fighting Ahura Mazda with evil and destruction. Every person can choose who to follow, Good or Evil, but Good will ultimately prevail.
Zoroastrianism was the state religion of the Sassanid Empire in Persia, but was almost wiped out by the Muslim Invasion. In the 14th Century, the Timurids from Central Asia conquered Persia from the Muslims and re-established Zoroastrianism as the state religion. Today Zoroastrianism is the dominant religion in Greater Khorasan and Central Asia.
There are two main communities of Zoroastrians, the larger community of Iranian, Khorasani, and Central Asian Zoroastrians, and the smaller community of the Parsis in India, who fled the Muslim persecution before the invasion of Timur the Zoroastrian and re-establishment of Zoroastrianism as the state religion.