The eleventh-century Byzantine compiler Cedrenus includes a unique story in the midst of his otherwise traditional and hagiographic material on the emperor Constantine. Mentioning the outbreak of war between the Roman and Persian empires, he describes the cause of the breakdown of peace somewhat as follows. A certain Metrodorus, who was of Persian origin, went to visit the Brahmins in India to study philosophy and won the reputation of being a holy man through his asceticism. He also built water mills (...) and baths, unknown to the Indians till that time. Having acquired this reputation, he entered the temples and took away many precious stones and pearls. He also received gifts from the king of the Indians. On his return to Byzantium he gave them to the emperor Constantine as being gifts of his own. When Constantine expressed his astonishment, Metrodorus said he had sent other gifts by the land route but that they had been detained by the Persians. Constantine then wrote a strong protest to Sapor demanding the gifts but received no reply; thus the peace was broken. This remarkable conte, more appropriate to the Arabian Nights than to sober history, is generally supposed to be referred to in a passage in Ammianus. Towards the end of a long section commenting on the personality and achievements of Julian, Ammianus turns briefly to the question of the ultimate responsibility for the Persian War which ended so disastrously for Julian and the Roman Empire: et quoniam eum obtrectatoribus novos bellorum tumultus ad perniciem rei communis insimulant concitasse, sciant docente veritate perspicue, non Iulianum sed Constantinum ardores Parthicos succendisse, cum Metrodori mendaciis avidius acquiescit, ut dudum rettulimus plane. (shrink)