Before considering this new phase through which the human mind was to pass it is necessary to guard against a common misapprehension in the use of the term "Middle Ages". Our historical textbooks usually include in that period the happenings between the dissolution of the Roman Empire and the voyages of Columbus or the opening of the Protestant revolt. To the student of intellectual history this is unfortunate, for the simple reason that almost all the ideas and even institutions of the Middle Ages, such as the church and monasticism and organized religious intolerance, really originated in the late Roman Empire. Moreover, the intellectual revolution which has ushered in the thought of our day did not get well under way until the seventeenth century. So one may say that medieval thought began long before the accepted beginning of the Middle Ages and persisted a century or so after they are ordinarily esteemed to have come to an end. We have to continue to employ the old expression for convenience' sake, but from the standpoint of the history of the European mind three periods should be distinguished, lying between ancient Greek thought as it was flourishing in Athens, Alexandria, Rhodes, Rome, and elsewhere at the opening of the Christian era, and the birth of modern science some sixteen hundred years later. The first of these is the period of the Christian Fathers, culminating in the authoritative writings of Augustine, who died in 430. By this time a great part of the critical Greek books had disappeared in western Europe. As for pagan writers, one has difficulty in thinking of a single name (except that of Lucian) later than Juvenal, who had died nearly three hundred years before Augustine. Worldly knowledge was reduced to pitiful compendiums on which the mediaeval students were later to place great reliance. Scientific, literary, and historical information was scarcely to be had. The western world, so far as it thought at all, devoted its attention to religion and all manner of mystical ideas, old and new. As Harnack has so well said, the world was already intellectually bankrupt before the German invasions and their accompanying disorders plunged it into still deeper ignorance and mental obscurity. The second, or "Dark Age", lasted with only slight improvement from Augustine to Abélard, about seven hundred years. The prosperous _villas_ disappeared; towns vanished or shriveled up; libraries were burned or rotted away from neglect; schools were closed, to be reopened later here and there, after Charlemagne's educational edict, in an especially enterprising monastery or by some exceptional bishop who did not spend his whole time in fighting.