New Persian literature, like that of many other countries, begins with poetry. Phonetically and grammatically, the degree of evolution from Old Persian to Middle Persian is considerable, the differences being comparable with the differences between Latin and French, for example. The emergence of the New Persian language and literature presents considerable historical problems. In an account passed down by the Fihrist, Ibn al-Muqaffac describes the linguistic situation in Iran at the end of the Sāsānian period. The Iranians, he says in effect, have five languages, including pahlavī, darī, pārsī, suryānī, and khūzī. The emergence of Persian literature involved the elevation of a widely distributed oral language, darī, to the rank of a language of general culture. Persian poetry is indebted both to Arabic literature and to the Iranian tradition. Since Persian poetry originated in courts for the glorification of Iranian princes, lyrical poetry was the first genre to appear.

This chapter touches on the era of the "Great Saljuqs" only in its last phase, that is, towards the end of the reign of Sultan Sanjar, a monarch who was then decadent though he was later idealized. The Saljuqs are a remarkable phenomenon, and we should therefore cast at least a cursory glance back to the period of their real greatness; for this wholly Turkish dynasty, holding sway over an immense area, played a very considerable part in the expansion of the Persian literary language and of Persian culture in general. The official language was Persian, and in it was conducted the official correspondence of the court, in contrast to the practice under Mahmud. Poetry also flourished during the period of the decline and fall of Saljuq rule, but the forms perfected by the old masters were already dying out and poetry was developing in an entirely new direction. Sa'di's principal didactic works are the Bustdn and the Gulistdn.