If Sapor did not in the long run succeed in gaining great advantages, it was through no merit of the emperor Constantine, who was invariably defeated when he took command in person, as, for example, in the famous battle by night at Singara (Shingar, Arabic Sinjar) (348 A.D.). The main reason was that the great emperors Diocletian and Constantine had put the fortresses into admirable condition and taken other excellent measures for the protection of the provinces exposed to attack. It was a great thing gained that the Persians, even when victorious, could hardly penetrate into western Mesopotamia. Moreover the king’s forces were not large enough for him to leave garrisons in all the fortresses which he took. Thus in 360 Amida (Amid), which Sapor had taken after a long siege and with heavy loss in the previous year, was found by the Romans unoccupied. The Romans were also favoured by the circumstance that the king was at the same time engaged in conflict with several barbarous tribes. The third siege of Nisibis had almost come to a successful conclusion when he was obliged suddenly to depart to Khorasan, where his presence was urgently required. The wars in the East brought about a long truce (from 350 to 358), interrupted only by small predatory excursions. But by the time negotiations were opened on the Roman side (356-358) Sapor had concluded peace with his enemies in the East, and offered terms which it was quite impossible to accept. In 359 and 360 hostilities were resumed with energy, and Sapor took several important fortresses. Another interval of repose ensued; but in 363 a change came over the whole conduct of the war. [Sidenote: [363-379 A.D.]] Vigorous, ambitious, and proved in arms, Julian, now sole emperor, determined to follow the example of Trajan, Septimius Severus, and Carus, and march straight upon the enemy’s capital. On the 5th of March he left Antioch, went first to Mesopotamia, and thence proceeded rapidly down the Euphrates. He ravaged Persian territory with fire and sword, took several cities after a short siege, among them Mahoz Malka, one of the royal cities close to Ctesiphon. He even reached Seleucia; but realising that he was not able to take the strongly fortified city of Ctesiphon on the far side of the Tigris by storm, he turned to retreat along the left bank of the river. Here for the first time Sapor’s troops began to annoy him seriously. None the less he would certainly have led the army back into Roman territory without heavy loss, but he was mortally wounded in an engagement on the 26th of June, 363.