While the invasion of Rome by the Barbarians in the fifth century and the capture of Alexandria by the Arabs in the early part of the seventh gave rise to an enormous loss of valuable books relating to medicine and philosophy in general, these were by no means the only occasions when books were probably destroyed in great quantities. Wars were frequent in those days and towns were constantly being sacked. Everywhere throughout the East the modern traveler encounters the ruins of large cities, and in those cities--the centres, as they were, of wealth and culture--there must have been large collections of books. It is not at all strange, therefore, that when the Caliph Almansur made a serious beginning of the work which was to convert the Arabs into rivals of the ancient Greeks, he should have found a great scarcity of medical works which, after being translated, were to serve as manuals of instruction. However, his ambition was very great, his wealth almost inexhaustible, and his associates eager to aid him in realizing the _renaissance_ which he had planned for his people; and, as will appear later on, he and those who aided him eventually succeeded in overcoming this apparently insurmountable obstacle. Among the medical books which, upon the approach of the Goths, were carried from Rome and other cities to different monasteries for safe keeping there must have been very few that were written in Latin, and yet these were the only ones from which the monks individually could derive any benefit. Several centuries later, when all the monasteries of Italy and the East were visited by those who were searching eagerly for original manuscript copies of the Greek medical writers,--Hippocrates, Soranus, Rufus of Ephesus, Aretaeus, Dioscorides, Galen,--it was found that such copies existed in a number of these institutions, thus showing that the monks had been actuated by unselfish and far-seeing loyalty to the best interests of mankind when they rescued these particular treasures from the hands of the enemy. They themselves could make no use of them, being unable to read Greek, but they knew their priceless value to medical science. The Latin treatises which they had also rescued, and of which they made excellent use during the succeeding centuries, were those of Celsus, Scribonius Largus, Pliny the Elder (to a slight degree only) and Caelius Aurelianus. PART II MEDIAEVAL MEDICINE CHAPTER XVII THE CONDITION OF MEDICINE AT BYZANTIUM DURING THE EARLY PART OF THE MIDDLE AGES