On the Eastern frontier peace had remained unbroken throughout Constantine’s long reign. Persia had been so shattered by Galerius that King Narses made no attempt to renounce the humiliating treaty which had been imposed upon him. His son, Hormisdas, had likewise acquiesced in the loss of Armenia and what were known as the five provinces beyond the Tigris, and when Hormisdas died, leaving a son still unborn, there was a long regency during which no aggressive movement was made from the Persian side. However, this son, Sapor, proved to be a high-spirited, patriotic, and capable monarch, who was determined to uphold and assert the rights of Persia. It is not known how the peaceful relationship, which had so long subsisted between his country and Rome, came to be broken. According to Eusebius,[118] Sapor sent an embassy to the Emperor, which was received with the utmost cordiality, and Constantine, we are told, took the opportunity of sending back by these same envoys a letter commending to his favourable regard the Christians of Persia. The document contained a very tedious and involved confession of faith by the Emperor, who affirmed his devotion to God and declared his horror at the sight and smell of the blood of sacrifice. “The God I serve,” said Constantine, “demands from His worshippers nothing but a pure mind and a spirit undefiled.” Then he reminded Sapor how the persecutors of the Church had been destroyed root and branch, and how one of them, Valerian, had graced the triumph of a Persian king. He, therefore, confidently committed the Christians, who “honoured by their presence some of the fairest regions of Persia,” to the generosity and protection of their sovereign. ----- Footnote 118: _De Vita Const._, iv., p. 8. -----