The reign of Sapor II. is estimated variously, at 69, 70, 71, and 72 years; but the balance of authority is in favor of seventy.  He was born in the course of the year A.D. 309, and he seems to have died in the year after the Roman emperor Valens, or A.D. 379.  He thus reigned nearly three-quarters of a century, being contemporary with the Roman emperors, Galerius, Constantine, Constantius and Constans, Julian, Jovian, Valentinian I., Valens, Gratian, and Valentinian II.

This long reign is best divided into periods.  The first period of it extended from A.D. 309 to A.D. 337, or a space of twenty-eight years.  This was the time anterior to Sapor’s wars with the Romans.  It included the sixteen years of his minority and a space of twelve years during which he waged successful wars with the Arabs.  The minority of Sapor was a period of severe trial to Persia.  On every side the bordering nations endeavored to take advantage of the weakness incident to the rule of a minor, and attacked and ravaged the empire at their pleasure.  The Arabs were especially aggressive, and made continual raids into Babylonia, Khuzistan, and the adjoining regions, which desolated these provinces and carried the horrors of war into the very heart of the empire.  The tribes of Beni-Ayar and Abdul-Kais, which dwelt on the southern shores of the Persian Gulf, took the lead in these incursions, and though not attempting any permanent conquests, inflicted terrible sufferings on the inhabitants of the tracts which they invaded.  At the same time a Mesopotamian. chieftain, called Tayer or Thair, made an attack upon Otesiphon, took the city by storm, and captured a sister or aunt of the Persian monarch.  The nobles, who, during Sapor’s minority, guided the helm of the State, were quite incompetent to make head against these numerous enemies.  For sixteen years the marauding bands had the advantage, and Persia found herself continually weaker, more impoverished, and less able to recover herself.  The young prince is said to have shown extraordinary discretion and intelligence.  He diligently trained himself in all manly exercises, and prepared both his mind and body for the important duties of his station.  But his tender years forbade him as yet taking the field; and it is not unlikely that his ministers prolonged the period of his tutelage in order to retain, to the latest possible moment, the power whereto they had become accustomed.  At any rate, it was not till he was sixteen, a later age than Oriental ideas require, that Sapor’s minority ceased—­that he asserted his manhood, and, placing himself at the head of his army, took the entire direction of affairs, civil and military, into his own hands.