atashIran is the ancient name of Persia, and it is derived from the root "Arya" or Aryan, the Indo-European branch of peoples who settled in that land. The Aryans of ancient Iran were Mazdayasni Zarathushtris, ie. Worshippers of Ahura Mazda (the name of God in Avestan) as revealed by the ancient prophet Zarathushtra, thousands of years before Christ.
However, all the ancient Zoroastrian scriptures speak of an earlier homeland from where our people came, the lost "Airyane Vaejahi" or seedland of the Aryans. From this homeland, the Indo- Europeans or Aryans moved to upper India, Iran, Russia and the nations of Europe such as Greece, Italy, Germany, France, Scandinavia, England, Scotland and Ireland.
Sanskrit, Latin, Avestan are all sister languages, and the present day upper Indian, Persian and European languages are related eg. Baradar in persian = Brata in sanskrit = Brother in english. "Persia" is actually a late European term for the land of "Farsi" language ie. Iran. The Arabic phase in Iran only began 1300 years ago, and we had to escape to India to preserve our Zoroastrian religion.