Throughout his reign, the Shah Yazdgird I attempted to harness Christian symbolism while integrating it with the majority Iranian Zoroastrian culture. During his twenty-one years as Shah, Yazdgird undertook a wide-reaching program involving the Syriac community across borders. Though his projects attempted to achieve various goals, the common objective among them was to establish both internal and external stability for his empire. Although Yazdgird ultimately failed in doing so, his endeavors initiated a chain of events that would eventually bear fruit centuries later. This article will explore Yazdgird’s Christian ventures in the context of Richard Payne’s recent theory of Iranian Cosmopolitanism. The projects in question are the creation of the frontier martyr cult, the foundation of Martyropolis, and the calling of the Council of Mar Ishaq. In the second section, these developments will be placed within the broader context of Christianity’s evolving status in Iran from the fifth to the seventh century. Within this context, it seems that Yazdgird was indeed a forerunner in his treatment of Christianity and its adherents.