In the Sasanian empire, the relation to power of the different strands of Christianity (East-Syrian Dyophysite, West-Syrian Miaphysite, Chalcedonian) or Christian-oriented groups, partly derived from the landmark movements of deportation and missions starting in the East Roman lands, remained unsettled during the whole dynastic period (from the 3rd to the 7th centuries), moving from integration to defensive relation. Therefore, the question of the conversion to Christianity is naturally correlated to the notion of identity affirmation on the one hand, within a minority context and an ethnic, cultural and religiously plural environment,1 and to that of political loyalty towards the Persian king on the other, seeing that adhesion to Christianity within the Iranian territory challenged the very unity of the political body incarnated by the Sovereign. Periods of persecution of religious minorities, and specifically Christian minorities, between the 4th century and the Arab period, led to a vast literary production that has fundamentally contributed to the shaping of identity in the Church of the East. Syriac sources present several types of accounts of conversion. The Acts of the Persian Martyrs often give priority to the conversion of great characters from the Mazdean society (from the 6th century onwards especially); some hagio-graphies in fact mention cases of collective and widespread conversion (over a whole region for instance). In these accounts, the Sasanian king appears as the defender of Mazdaism, the official religion of the Empire, who intervenes on different levels in the process of conversion through a contrasting political approach, sometimes coercive, and sometimes supporting towards religious movements. These ambiguities lead to questions regarding the underlying interests behind such royal behaviour, but also in parallel concerning the writing process leading Christians to rewrite the persecuting king into a Christianised Sovereign.