Rome on her part made ready to resist the invasion which she knew to be impending. A powerful army was sent to guard the East under count Trajan, and Vadomair, ex-king of the Alemanni; but so much regard for the terms of the recent treaty was still felt, or pretended, that the generals received orders to be careful not to commence hostilities, but to wait till an attack was made on them. They were not kept long in expectation. As soon as winter was over, Sapor crossed the frontier (A.D. 371) with a large force of native cavalry and archers, supported by numerous auxiliaries, and attacked the Romans near a place called Vagabanta. The Roman commander gave his troops the order to retire; and accordingly they fell back under a shower of Persian arrows, until, several having been wounded, they felt that they could with a good face declare that the rupture of the peace was the act of the Persians. The retreat was then exchanged for an advance, and after a brief engagement the Romans were victorious, and inflicted a severe loss upon their adversaries. But the success was not followed by results of any importance. Neither side seems to have been anxious for another general encounter; and the season for hostilities was occupied by a sort of guerilla warfare, in which the advantage rested alternately with the Persians and the Romans. At length, when the summer was ended, the commanders on either side entered into negotiations; and a truce was made which allowed Sapor to retire to Ctesiphon, and the Roman emperor, who was now personally directing the war, to go into winter quarters at Antioch. After this the war languished for two or three years. Valens was wholly deficient in military genius, and was quite content if he could maintain a certain amount of Roman influence in Armenia and Iberia, while at the same time he protected the Roman frontier against Persian invasion. Sapor was advanced in years, and might naturally desire repose, having been almost constantly engaged in military expeditions since he reached the age of sixteen. Negotiations seem to have alternated with hostilities during the interval between A.D. 371 and 376; but they resulted in nothing, until, in this last-named year, a peace was made, which gave tranquillity to the East during the remainder of the reign of Sapor.