In the pursuit of identifying the sources of early Islamic art, research over the past century has explored various dimensions of artistic influence. One of the most recent views is that of Guitty Azarpay, who, on the basis of the dominance of Arab culture in pre-Mongol manuscript illumination, considers secondary Sogdian murals with popular and non-epic themes to have been the most influential genre of Eastern art on Islamic-period art. The present study, based on the classification of the aforementioned manuscripts into two groups—works from Jibāl–al-Jazīra and those from Baghdad—examines the dimensions of this influence in order to assess Azarpay’s interpretation and identify the influential position of Sogdian epic painting, as the most important artistic genre of Transoxanian civilization. To this end, ten Islamic manuscripts and 26 Transoxanian murals were examined. The influence of epic-painting traditions was identified in two categories: 1.representations rooted in Sogdian–Turkic cultural life, such as depictions of warrior women and celestial beings; 2.the direct adoption of Sogdian artistic motifs and techniques, such as colored backgrounds, detailed rendering of military garments, and balanced compositions. The analysis shows that the artistic traditions of epic painting transmitted to the Transoxanian Turks, spread along the cultural route from Khurasan to al-Jazīra, giving rise to a distinctive pre-Mongol manuscript tradition, distinct from Abbasid and Mamluk artistic production. Contrary to Azarpay’s interpretation, the findings reveal that the predominance of Iranian culture in this sphere is reflected in the prominent presence of epic-painting visual traditions in regional manuscript illumination.