But Egypt itself, the only province which had been exempt, since the time of Diocletian, from foreign and domestic war, was again subdued by the successors of Cyrus. Pelusium, the key of that impervious country, was surprised by the cavalry of the Persians; they passed, with impunity, the innumerable channels of the Delta, and explored the long valley of the Nile, from the pyramids of Memphis to the confines of Ethiopia. Alexandria might have been relieved by a naval force, but the archbishop and the prefect embarked for Cyprus; and Chosroes entered the second city of the empire, which still preserved a wealthy remnant of industry and commerce. His western trophy was erected, not on the walls of Carthage, but in the neighbourhood of Tripoli; the Greek colonies of Cyrene were finally extirpated; and the conqueror, treading in the footsteps of Alexander, returned in triumph through the sands of the Libyan desert. In the same campaign, another army advanced from the Euphrates to the Thracian Bosporus; Chalcedon surrendered after a long siege, and a Persian camp was maintained above ten years in the presence of Constantinople. The sea coast of Pontus, the city of Ancyra, and the isle of Rhodes, are enumerated among the last conquests of the great king; and if Chosroes had possessed any maritime power, his boundless ambition would have spread slavery and desolation over the provinces of Europe. [Illustration: A BYZANTINE PRIEST] From the long-disputed banks of the Tigris and Euphrates, the reign of the grandson of Nushirvan was suddenly extended to the Hellespont and the Nile, the ancient limits of the Persian monarchy. But the provinces, which had been fashioned by the habits of six hundred years to the virtues and vices of the Roman government, supported with reluctance the yoke of the barbarians. The idea of a republic was kept alive by the institutions, or at least by the writings, of the Greeks and Romans, and the subjects of Heraclius had been educated to pronounce the words of liberty and law. But it has always been the pride and policy of oriental princes to display the titles and attributes of their omnipotence; to upbraid a nation of slaves with their true name and abject condition, and to enforce, by cruel and insolent threats, the rigour of their absolute commands.