Res Gestae

The great God of Heliopolis, heavenly, mighty Apollo, son of Heron, whom the Sun hath loved, whom the Gods hath honoured, the ruler over all the earth, whom the Sun hath chosen, a king valiant for Mars, whom Ammon loveth, and he that is all-radiant, having set apart the king eternal; and so on.

In the consulship of Datianus and Cerealis, while all provisions in Gaul were being made with very careful endeavour, and dismay due to past losses halted the raids of the savages, the king of Persia was still encamped in the confines of the frontier tribes; and having now made a treaty of alliance with the Chionitae and Gelani, the fiercest warriors of all, he was on the point of returning to his own territories, when he received Tamsapor’s letter, stating that the Roman emperor begged and entreated for peace.

Therefore, imagining that such a step would not be attempted unless the fabric of the empire were weakened, he swelled with still greater pride, embraced the name of peace, and proposed hard conditions; and dispatching one Narseus with gifts as his envoy, he sent a letter to Constantius, in no wise deviating from his native haughtiness, the tenor of which, as we have learned, was as follows:—

I Sapor, King of Kings, partner with the Stars, brother of the Sun and Moon, to my brother Constantius Caesar offer most ample greeting. I rejoice and at last take pleasure that you have returned to the best course and acknowledged the inviolable sanction of justice, having learned from actual experience what havoc has been caused at various times by obstinate covetousness of what belongs to others.