Constantine, with all the Roman world at his feet, and all its responsibilities weighing on his mind, was far too able a man to overlook the great need of the day—a more conveniently placed administrative and military centre for his empire. He required a place that should be easily accessible by land and sea—which Rome had never been in spite of its wonderful roads—that should overlook the Danube lands, without being too far away from the East; that should be so strongly situated that it might prove an impregnable arsenal and citadel against barbarian attacks from the north; that should at the same time be far enough away from the turmoil of the actual frontier to afford a safe and splendid residence for the imperial court. The names of several towns are given by historians as having suggested themselves to Constantine. First was his own birth-place—Naissus (Nisch) on the Morava, in the heart of the Balkan Peninsula; but Naissus had little to recommend it: it was too close to the frontier and too far from the sea. Sardica—the modern Sofia in Bulgaria—was liable to the same objections, and had not the sole advantage of Naissus, that of being connected in sentiment with the emperor’s early days. Nicomedia on its long gulf at the east end of the Propontis was a more eligible situation in every way, and had already served as an imperial residence. But all that could be urged in favour of Nicomedia applied with double force to Byzantium, and, in addition, Constantine had no wish to choose a city in which his own memory would be eclipsed by that of his predecessor Diocletian, and whose name was associated by the Christians, the class of his subjects whom he had most favoured of late, with the persecutions of Diocletian and Galerius. For Ilium, the last place on which Constantine had cast his mind, nothing could be alleged except its ancient legendary glories, and the fact that the mythologists of Rome had always fabled that their city drew its origin from the exiled Trojans of Æneas. Though close to the sea it had no good harbour, and it was just too far from the mouth of the Hellespont to command effectually the exit of the Euxine. Byzantium, on the other hand, was thoroughly well known to Constantine. For months his camp had been pitched beneath its walls; he must have known accurately every inch of its environs, and none of its military advantages can have missed his eye. Nothing, then, could have been more natural than his selection of the old Megarian city for his new capital. Yet the Roman world was startled at the first news of his choice; Byzantium had been so long known merely as a great port of call for the Euxine trade, and as a first-class provincial fortress, that it was hard to conceive of it as a destined seat of empire.