What is Zoroastrianism?

Zoroastrianism or Mazdayasna is one of the world's oldest continuously practiced religions. It is a heterodox yet orthopraxic faith centered in a dualistic cosmology of good and evil and an eschatology predicting the ultimate conquest of evil with theological elements of henotheism, monotheism/monism, and polytheism. Ascribed to the teachings of the Iranian-speaking spiritual leader Zoroaster (also known as Zarathushtra), it exalts an uncreated and benevolent deity of wisdom, Ahura Mazda (Wise Lord), as its supreme being. Major features of Zoroastrianism, such as messianism, judgment after death, heaven and hell, and free will may have influenced other religious and philosophical systems, including Second Temple Judaism, Gnosticism, Greek philosophy, Christianity, Islam, the Bahá'í Faith, and Buddhism.

With possible roots dating back to the second millennium BCE, Zoroastrianism enters recorded history in the 5th century BCE. Along with a Mithraic Median prototype and a Zurvanist Sassanid successor, it served as the state religion of the pre-Islamic Iranian empires for more than a millennium, from around 600 BCE to 650 CE. Zoroastrianism declined from the 7th century onwards following the Muslim conquest of Persia of 633–654. Recent estimates place the current number of Zoroastrians at around 190,000, with most living in India and in Iran; their number has been thought to be declining.