Though deprived of a liberty which had for long years been almost nominal, Byzantium could not be deprived of its unrivalled position for commerce. It continued to flourish under the _Pax Romana_, the long-continued peace which all the inner countries of the empire enjoyed during the first two centuries of the imperial _régime_, and is mentioned again and again as one of the most important cities of the middle regions of the Roman world. But an evil time for Byzantium, as for all the other parts of the civilized world, began when the golden age of the Antonines ceased, and the epoch of the military emperors followed. In 192 A.D., Commodus, the unworthy son of the great and good Marcus Aurelius, was murdered, and ere long three military usurpers were wrangling for his blood-stained diadem. Most unhappily for itself Byzantium lay on the line of division between the eastern provinces, where Pescennius Niger had been proclaimed, and the Illyrian provinces, where Severus had assumed the imperial style. The city was seized by the army of Syria, and strengthened in haste. Presently Severus appeared from the west, after he had made himself master of Rome and Italy, and fell upon the forces of his rival Pescennius. Victory followed the arms of the Illyrian legions, the east was subdued, and the Syrian emperor put to death. But when all his other adherents had yielded, the garrison of Byzantium refused to submit. For more than two years they maintained the impregnable city against the lieutenants of Severus, and it was not till A.D. 196 that they were forced to yield. The emperor appeared in person to punish the long-protracted resistance of the town; not only the garrison, but the civil magistrates of Byzantium were slain before his eyes. The massive walls “so firmly built with great square stones clamped together with bolts of iron, that the whole seemed but one block,” were laboriously cast down. The property of the citizens was confiscated, and the town itself deprived of all municipal privileges and handed over to be governed like a dependent village by its neighbours of Perinthus.