During these latter years the eastern half of the empire was chiefly guarded by Odenathus of Palmyra, the brave and faithful ally of Rome, under whose wise rule his country for a short time held a rank among the empires of the world, which it never could have gained but for an union of many favourable circumstances. The city and little state of Palmyra is situated about midway between the cities of Damascus and Babylon. Separated from the rest of the world, between the Roman and the Parthian empires, Palmyra had long kept its freedom, while each of those great rival powers rather courted its friendship than aimed at conquering it. But, as the cause of Rome grew weaker, Odenathus wisely threw his weight into the lighter scale; and latterly, without aiming at conquest, he found himself almost the sovereign of those provinces of the Roman empire which were in danger of being overrun by the Persians. Valerian himself was conquered, taken prisoner, and put to death by Sapor, King of Persia; and Gallienus, his son, who was idling away his life in disgraceful pleasures in the West, wisely gave the title of emperor to Odenathus, and declared him his colleague on the throne. [Illustration: 155.jpg A HAREM WINDOW] No sooner was Valerian taken prisoner than every province of the Roman empire, feeling the sword powerless in the weak hands of Gallienus, declared its own general emperor; and when Macrianus, who had been left in command in Syria, gathered together the scattered forces of the Eastern army, and made himself emperor of the East, the Egyptians owned him as their sovereign. As Macrianus found his age too great for the activity required of a rebel emperor, he made his two sons, Macrianus, junior, and Quietus, his colleagues; and we find their names on the coins of Alexandria, dated the first and second years of their reign. But Macrianus was defeated by Dominitianus at the head of a part of the army of Aureolus, who had made himself emperor in Illyricum, and he lost his life, together with one of his sons, while the other soon afterwards met with the same fate from Odenathus.