The reign of King Khusrō I (531–579 CE) was a key chapter in the history of the Persian Empire, but it was also an important period for the development of the Church of the East. The Martyrdom of Mar Grigor Piran-Gušnasp and the Martyrdom of Mar Yazd-panah offer a panoramic perspective onto the social, religious, and political life of Christians in the Sasanian Empire at this time. According to these contemporary accounts, the death of Grigor, the general of the Sasanian king's armies and a convert from Zoroastrianism to Christianity, triggered the conversion of other Zoroastrian notables, including the courtier ʿAwira and Yazd-panāh, a judge who also died as a martyr three years after Grigor. This volume provides a critical text and commentary, as well as the first translation into English, of these two East Syrian texts, which have received little scholarly attention, although they are among the few Syriac martyr accounts from this period. These texts demonstrate how Persian Christians, despite sporadic persecution, were able to maintain a distinct identity while simultaneously acculturating to the norms of Iranian society, even taking on significant offices within the Sasanian administration.