Though based on the fire-worship, Zoroastrianism emerged as an independent religion. M.Bors pointed out that Zoroastrianism had been the most ancient among the prophetic religions. Qatas, part of Avesta, the Holy book of Zoroastrianism, was sent down to Zoroaster, a religious teacher, and prophet (6th century B.C.). According to some sources, Zoroaster’s father came from Azerbaijan. According to Zoroastrianism, the world lies on two components – the Good and the Evil, which lead to the constant struggle. The world of Light, Goodness, and Justice are embodied in Hormuzd (Ahura-Mazda), while the world of Darkness, the Evil, and Tyranny is embodied in Ahriman (Ahura-Manyu). The struggle will finally end with the triumph of the Good, and the active followers of Ahura-Mazda in his battle against Evil and Tyranny will meet with the happiness of eternity. The ideas of the happiness of eternity, sins, and good deeds prove the maturity of Zoroastrianism. Zoroaster urged people to be just and fair and struggle against any meanness.
Fire occupied an important place in the Zoroastrian beliefs. Therefore Zoroastrians were often considered fire-worshippers. Zoroastrians considered human corpses nasty and did not bury them into the ground but kept them in unique places in the mountains for birds and worms to eat. Only after that, they buried gathered and purified bones into the ground.
The Zoroastrian beliefs acquired the form of dogma in the 3rd century B.C. Due to Sasanians’ military and political progress, Zoroastrianism spread on the territory of Azerbaijan till Derbend. Iranian Zoroastrians were moved to the country to spread the new religion. At the same time, Zoroastrianism adopted local features in Azerbaijan. The Caucasus Albanians buried jewelry and kitchen utensils together with their dead owners. It is also known that after the purification of bones of dead people, they were placed in a big pot-like coffin and thus buried. The dead people were also buried in pottery coffins, underground tombs, and hollow graves.
Constant wars between Sassanid and Byzantines for expanding their areas of influence in Azerbaijan resulted in strengthening either Christianity or Zoroastrianism. In such conditions, Islam found a way to the most intensive and peaceful spreading in the country. Since the Middle Ages, Zoroastrianism could not react to the cultural and political requirements of the time. Therefore it lost its actuality.