Wherever Zoroastrians live, fled or anything, they kept a piece of Iran with them (Iranian culture, theology, history). Just like a bank where you can deposit your gold and money for the rest of your family and future generations, Zoroastrians (both Irani and Parsi branche) didthis with the Avesta.
Else abrahamic terrorists and bookburners (jews, muslims, christians) might have destroyed all of the texts.
According to an account in
Tarikh al-Tabari by
Al-Tabari, the Arab Commander
Sa'ad ibn Abi Waqqas wrote to Caliph
Umar ibn al-Khattab asking what should be done with the books at
Ctesiphon. Umar wrote back:
"If the books contradict the Qur'an, they are blasphemous. On the other hand, if they are in agreement, they are not needed, as for us Qur'an is sufficient." Thus, the huge library was destroyed and the books, the product of the generations of Persian scientists and scholars were thrown into fire or the
Euphrates.
According to Dawlatshah,
Abdollah-ibn-Tahir, an Arabicized Persian, and governor of Khorasan for the
Abbasid caliphs, banned publication in Persian and by his order all the Zoroastrians were forced to bring their religious books to be thrown in the fire. As a result, many literary works written in Pahlavi script disappeared.
According to
Mary Boyce, Zoroastrians living under
Christian rule in
Asia Minor were noted to have undergone hardship, notably during the long
conflict between the Roman Empire and Persia.
Christians living in Sassanian-held territory were noted to have destroyed many fire-temples and Zoroastrian places of worship!!! Christian priests deliberately extinguished the sacred fire of the Zoroastrians and characterized adherents as "followers of the wicked Zardusht (Zoroaster), serving false gods and the natural elements."
In anticipation for the coming of the Messiah, the
Jews of Isfahan celebrated the conquest of the city by the Arabs. According to Abu Noʿaym (I, pp. 21-22) the Jews of Isfahān, while dancing and playing music, went to the gate of the city to receive the Arab conquerors.
Any Iranian attacking/insulting zoroastrians is either son of an arab or son of a jew. There is no other possibility or explanation available.
