THUS SPOKE ZARATHUSTRA: Origins of the Apocalypse

According to tradition, Zarathustra was born not far from present-day Tehran into an impoverished family of warriors. Researchers are still arguing about when this event occurred. He displayed an interest in religion and was trained in sacrifice and sacred chanting from childhood. When he reached the age of thirty, he was lifted in spirit to the throne of the supreme deity Ahura Mazda, who directed him to the people to choose between him and the opposing evil spirit Angra Mainyu.
Zarathustra preached religious reforms and taught his followers to lead righteous lives with good intentions and thoughts. To those who will stand up for good, the prophet promised prosperity in the earthly life and immortality in the world to come. He also predicted the final victory of the heavenly host Ahura Mazda, which will happen after Doomsday, when the earth will be purified and the forces of evil will be ultimately defeated.
In ancient times Zoroastrianism became the state religion of three Persian empires - during the rule of the Achaemenids (c. 550 - 300 BC) and Parthian kings (c. 141 BC - 222 AD), and the Sassanid dynasty (c. 224 - 439 AD). However, throughout its long history, Zoroastrianism failed to maintain the monotheistic orientation of Judaism and Islam.
Under Sasanids, the Zoroastrian priests inclined to the dualistic picture of the world where Ahriman (Angra Mainyu) was assigned a role of irreconcilable and equal rival to Ormazd (Ahura Mazda) in the battle between good and evil. Today a small community of Zoroastrian followers survives in India, Pakistan, and eastern Iran.
The Avesta, or the collection of sacred Zoroastrianism scriptures, was also finalized during the Sassanid dynasty in the 4th-5th centuries AD. One of the most ancient layers of the Avesta is the Gathas, liturgical hymns written in old Persian.
Already in the Gathas, we find references to the Day of Judgment and other apocalyptic themes. At the end of earthly life, everyone will have to walk across the Bridge of Separation, and Zoroaster himself will accompany the righteous, who on the other side of the bridge will await the House of Good Minds. A different, bitter fate awaits the sinners after death, whose conscience will torment their souls and whose home will be the House of Lies.
In the later commentaries on the Avesta, written during the era of Muslim domination in the 9th century AD, the descriptions of the Day of Judgment and the resurrection from the dead are more detailed. Here we read about dividing human history into three thousand-year epochs, beginning with goodness and prosperity and ending with chaos and decay.
Zoroaster proclaimed the first such era. At the end of the next period will come the promised third Deliverer - the herald of world renewal, which will mark the resurrection of the dead, the Last Judgement, and victory over evil and death. In those days, human history will come to its conclusion, and Ahura Mazda will establish his kingdom on earth, whose triumph will never cease.