This article offers a textual reconstruction and analysis of one of the most problematic couplets in the prelude to the story of Rostam and Sohrab in Ferdowsi's Shahnameh. In the Florence manuscript (614 AH), the couplet is recorded as: Nokhostīn tan az marg bebsāyadī/ Dalīr o javān khāk nabsāyadī. The wide variation in the manuscript readings has led some editors to omit the couplet from the text altogether, while others have proposed emendations that are difficult to justify. In this study, the extant manuscript readings are classified into two principal groups. Manuscript analysis suggests that the readings of the first group are most likely the result of scribal intervention, whereas the diversity of the second group indicates that the original form of the couplet should be sought within this group. The study therefore addresses two main questions: what is the most plausible reconstruction of the couplet in light of the manuscript evidence, and how does this reconstruction affect the arrangement of the verses in the prelude to the story of Rostam and Sohrab? The findings show that, once the couplet is restored, the prelude consists of a coherent sequence of six verses. Furthermore, examination of the manuscript tradition and the content of the subsequent verses indicates that numerous verses were added to this section after Ferdowsi. Most of these additions function as interpretive glosses composed in response to the ideas expressed in the original prelude.