How did Middle Persian literature influence Ferdowsi's Shah-namah?

Middle Persian literature served as the foundational source material for Ferdowsi’s Shah-namah, the Persian national epic.12

The primary influence was the Khvatay-namak, a Pahlavi (Middle Persian) chronicle that documented the history of Persian kings from mythical times through the Sasanian dynasty. This work was later translated into Arabic prose, and Ferdowsi based his epic poem largely on a subsequent Persian prose compilation of these materials.123

Beyond this central chronicle, Middle Persian literature provided specific narrative content that Ferdowsi incorporated into his work. For instance, the Pahlavi texts Ayadgar-i Zareran (concerning the establishment of Zoroastrianism) and Karnamag-i Ardashir (detailing the life of the founder of the Sasanian dynasty) are notable examples of Middle Persian works that contributed to the epic's legendary and historical framework. By versifying these inherited tales, Ferdowsi preserved the ancient myths, legends, and historical traditions of pre-Islamic Iran, giving them an enduring form that remains a cornerstone of Persian literature.3124