The Mongol conquest of Iran (1220–1231) coincided with the “literarization of history” across the Islamic world. In Iran, this phenomenon was characterized by the production of verse histories, modeled on Firdaūsī’s Shāh-nāmah. Ḥakīm Zajjājī’s Humāyūn-nāmah is one of the lesser-known examples of this genre, with modern scholars disputing both the date of its composition and the historical value of its contents. The present article analyzes the personalities and events described in the Humāyūn-nāmah, situating it in the broader community of letters cultivated by the Īlkhānid vizier Shams al-Dīn Juvaynī between 1249–1284. This article shows that the Humāyūn-nāmah was not only a piece of art, but a valuable eye-witness account of early Mongol rule in Iran (1220–1258).