The original Avesta consisted of 21 Nasks of which very few remain intact. Tabari (9th century Iranian historian) writes: "Thirty years after the reign of Kay Goshtasp, Zartusht Spitaman produced a book which was written in gold on 12,000 cowhides. Kay Goshtasp ordered that this book be kept in Dejh-Nebeshtak and be guarded by the Hierbads (the learned) away from the reach of the profane." The Pahlavi Dinkard (of the 9th century) states that two complete copies of the Avesta existed: the one kept in the Dezh-Nebeshtak of Persopolis and the other in Ganj-e-Shizegan, which most likely was in the town of Shiz of Azarpategan. When Alexander burned down Persopolis, the copy there was destroyed; but the one in Shizegan was translated into Greek and sent to Aristotle, Alexander's tutor. This translation has been lost. Bal'ami, historian and the minister of the Samanid kings (early 10th century), writes that Alexander "gathered Iranian philosophers and had their writings translated into Greek and sent them to Aristotle and other Greek philosophers. He destroyed the cities of Babel, Eragh and Pars, killed all men of eminence, and burned down all King Dara's (Darius) libraries."

The original Avesta consisted of 21 Nasks of which very few remain intact. Tabari (9th century Iranian historian) writes: "Thirty years after the reign of Kay Goshtasp, Zartusht Spitaman produced a book which was written in gold on 12,000 cowhides. Kay Goshtasp ordered that this book be kept in Dejh-Nebeshtak and be guarded by the Hierbads (the learned) away from the reach of the profane." The Pahlavi Dinkard (of the 9th century) states that two complete copies of the Avesta existed: the one kept in the Dezh-Nebeshtak of Persopolis and the other in Ganj-e-Shizegan, which most likely was in the town of Shiz of Azarpategan. When Alexander burned down Persopolis, the copy there was destroyed; but the one in Shizegan was translated into Greek and sent to Aristotle, Alexander's tutor. This translation has been lost. Bal'ami, historian and the minister of the Samanid kings (early 10th century), writes that Alexander "gathered Iranian philosophers and had their writings translated into Greek and sent them to Aristotle and other Greek philosophers. He destroyed the cities of Babel, Eragh and Pars, killed all men of eminence, and burned down all King Dara's (Darius) libraries."