The article is devoted to the unique medieval literary monument Vita Mahumeti which was written at the beginning of the 12th century by the bishop of Mainz Embrico. This essay presents an attempt at reconstructing historical reality in the literary work. The text of Embrico is examined in the cultural context of medieval literature. The author makes up her mind to find out the works of Syrian, Byzantine, Spanish literature as well as hagiographical writings from which Embrico adapted his Vita Mahumeti. The analysis shows that the historical figure of Muhammad had proved itself the most appropriate for creating the image of exemplary heresiarch. When describing the life of the prophet of islam Embrico essentially examined the distinction criteria between the true and the false saint. This work was found particularly important for the Christian Church struggling against heresies in the same period.