"epic of ancient Persian heroes"

 Shahnamah is a monumental creation myth and history of Persia, written by the poet Ferdowsi around 1000AD.  It details the ancient culture and legends of Persian, and is known as "The Persian Book of Kings".   Because of the purity of its text, it has been used to recreate the original Persian language following the influx of Arabic that accompanied the Islamization of the region.