Question: Is it possible to conclude that Ferdowsi’s Shahnama helped propagate Persian language features and the richness of literatures written after?
Answer: Quite right. Ferdowsi’s capable language expanded Persian language features. These features can be seen in Ferdowsi’s next generation’s literatures. This also exists in Ferdowsi’s contemporaries such as Unsuri and Farrukhi and the next generation such as Bayhaqi and Gardezi and the poets of Seljuq era like Anvari and Amir Mu’izzi. The important thing is that the natural evolution of the Persian language had already started. You could see its perfection at Bayhaqi’s prose and the poems of Seljuqid era. Mongol-era’s historians educated in Seljuqid and Khwarezmid era created eloquent yet somewhat difficult literatures like “Tarikh-i Jahāngushāy” (The History of The Wolrd Conqueror) by Juvayni and “Jāmi’ al-tawārīkh” (Compendium of Chronicles) by Rashid-al-Din Hamadani. But soon after the decreasing trend of the reading literatures started to the point of the hieratic and not pleasant prose of Safavid era.