The thesis addresses the persecution of the Christians in the Sasanian Empire that begun in 340 CE. Three primary questions are discussed: (1) Who were the persecuted Christians? (2) Who were the persecutors? And (3) why were the Christians persecuted? In essence, it is argued that the persecution was limited to a community of ascetic Christians on account of their abnegation of wealth and family, adherence to the martyrdom ideal, sexual abstinence and a rejection of core parts of the native religion, Mazdaism. Predominantly the Mazdean priesthood has been presented as the vanguard of the persecution. Rather the thesis proposes that it was carried out by the king, the nobility and the priesthood in concerted effort. Whereas the persecution has been perceived as the result of Constantine the Great's conversion to Christianity and therefore a matter of Christian loyalties to the Sasanians, the thesis suggests instead that Sasanian socio-economic and religious motivations drove the event. A special focus has been placed on Mazdaism and its ethical dualism, binary taxonomies, and judgement of human behavior in terms of either promoting the good or evil cosmic forces, where the ascetic Christians were perceived as supporters of the latter.