Early Islamic ta’rikh and adab chronicles record the seminal battle in which the Sasanian ruler Piruz I (d. 484 CE) met his end in Afghanistan at the hands of a numerically inferior Central Asian confederation. Two variants of this tradition exist. According to the most common narrative, it was the Hayatila (Hephthalites or “White Huns”) who dealt the Sasanians this crushing blow, whereas according to other sources, it was the Atrak (Turks). This paper asks what is the significance of this catastrophic defeat from the perspective of Islamic collective memory. I ague that in a similar way as the Sasanians’ loss to the Arabs at the Battle of Dhu Qar in the early 7th century, Piruz’s defeat at the hands of the Hayatila/Atrak serves in the Islamic narrative tradition to foreshadow the Arab conquest of the Persian empire occurring under the banners of Islam. My argument is evidenced by the conspicuous thematic similarities in reports of Piruz’s defeat and the epic futuh accounts relating the Muslim Arabs’ victories over the Persians and the Romans. For example, a prominent theme in both narratives is that of the moral superiority of the Persians’ opponents serving as the primary determinant of their triumph. In Piruz’s case, the sources underline that his defeat was a product of his violation of the covenant he made the Central Asian king, Akhshunvar, who had graciously assisted him in regaining his throne. Indeed, Akhshunvar is depicted as the voice of reason in this historical episode, displaying a belief in monotheism and even using Qur’anic phraseology in his warning to Piruz of the dire consequences for one who violates an oath. At the same time, accounts of this battle emphasize the trope of stereotypical Persian hubris, with the Sasanian ruler showing overconfidence in the numerical superiority of his imperial force, assuming that he would easily dispatch a less well-equipped army composed of nomadic warriors. As the first major defeat suffered by the Sasanians, this battle thus serves as a critical watershed from the perspective of Islamic historical memory, showing the vulnerability of the Sasanians for the first time, and demonstrating the potential of what could be accomplished by a pastoral-nomadic enterprise possessing the moral high ground.