For a thousand years, from the Hegira in 622 to the siege of Vienna in 1683, the peril of a Mahommedan conquest of Europe was almost continually present.
A passage in Ferishta seems to imply that the Afghans in the Sulimani mountains were already known by that name in the first century of the Hegira, but it is uncertain how far this may be built on.
Abu '1 Kasim Mansur (or Hasan), who took the nom de plume of Firdousi, author of the epic poem the Shahnama, or "Book of Kings," a complete history of Persia in nearly 60,000 verses, was born at Shadab, a suburb of Tus, about the year 329 of the Hegira (941 A.D.), or earlier.
On the Arab invasion this work was in great danger of perishing at the hands of the iconclastic caliph Omar and his generals, but it was fortunately preserved; and we find it in the 2nd century of the Hegira being paraphrased in Arabic by Abdallah ibn el Mokaffa, a learned Persian who had embraced Islam.
His "Book of Kings" was completed in the year 260 of the Hegira, and was freely circulated in Khorasan and Irak.