For the sake of all that it meant in the Roman Empire to look towards Rome at this time, however, it seemed better to the early Christians to establish the centre of their jurisdiction there. Necessarily, then, in all that related to the purely intellectual life, they came under the influences that were at work at Rome at this time. During the first centuries they suffered besides from the persecutions directed against them by the Emperors at various times, and these effectually prevented any external manifestations of the intellectual life on the part of Christians. It took much to overcome this serious handicap, but noteworthy progress was made in spite of obstacles, and by the time of Constantine many important officials of the Empire, the educated thinking classes of Rome, had become Christians. After the conversion of the Emperor opportunities began to be afforded, but political disturbances consequent upon barbarian influences still further weakened the old civilization until much of the intellectual life of it almost disappeared. Gradually the barbarians, finding the Roman Empire decadent, crept in on it, and though much more of the invasion was peaceful than we have been accustomed to think, the Romans simply disappearing because family life had been destroyed, children had become infrequent, and divorce had become extremely common, it was not long before they replaced the Romans almost entirely. These new peoples had no heritage of culture, no interest in the intellectual life, no traditions of literature or science, and they had to be gradually lifted up out of their barbarism. This was the task that Christianity had to perform. That it succeeded in accomplishing it is one of the marvels of history. The Church's first grave duty was the preservation of the old records of literature and of science. Fortunately the monasteries accomplished this task, which would have been extremely perilous for the precious treasures involved but for the favorable conditions thus afforded. Libraries up to this time were situated mainly in cities, and were subject to all the vicissitudes of fire and war and other modes of destruction that came to cities in this disturbed period. Monasteries, however, were usually situated in the country, were built very substantially and very simply, and the life in them formed the best possible safeguard against fire, which worked so much havoc in cities. As we shall see, however, not only were the old records preserved, but excerpts from them were collated and discussed and applied by means of direct observation. This led the generations to realize more and more the value of the old Greek medicine and made them take further precautions for its preservation.