During the period following the fall of Rome, the empire was overrun by barbarians from the north, and the magnificent baths, aqueducts and public edifices reared by the Romans with such painstaking care were suffered to fall into decay. So little in sympathy were the barbarians with the people they conquered and their institutions, that in time the inhabitants of many localities even forgot the uses to which the old works had been put; and had it not been for the Popes the supply of water to the city of Rome would have been cut off completely, while as it was the service was frequently interrupted. Following the fall of the Roman Empire there was a period of over one thousand years of intellectual darkness, during which no material progress was made; indeed, instead of progress a retrograde movement set in which left a lasting impression on the times. The little spark of knowledge that survived this period burned in the monasteries of the monks, who treasured and kept alive the spark of civilization. [Illustration: Destroyed Lead Font, Great Plumstead, Norfolk] The Dark Ages, as this period is called, if lacking in progress, were replete with adventure. During this period, which might equally well be called the Age of Romance, there sprung up a brotherhood of men noted for skill in combat, who were dubbed knights. There also spread a creed about that time that uncleanliness was next to godliness, and clergy and laymen vied with each other to see which could live in the most filthy manner. They associated in their minds luxury and cleanliness as inconsistent with godliness, while squalor and bodily filth were considered as outward indications of inward piety and sanctification. So it came to pass that bathing, instead of a daily practice, became uncommon; homes and inhabitants became filthy and streams polluted. Such violations of sanitary principles could not continue indefinitely without evil results, and scourge after scourge of filth diseases that swept over Europe and Asia, claiming over 40,000,000 victims, were due to the unsanitary condition that prevailed. The restless, seething, venturesome spirit of the times and the emotional zeal displayed in religious matters contributed greatly to the spread of pestilence. The crusades, starting out with a romantic and religious fervor, but with no set rules of conduct for guidance, and lacking a leader strong enough in discipline to hold in check men whose only claim to distinction lay in their powers in a tilt and their love of battle, soon degenerated into the most disorderly and lewd of rabble. Women camp-followers joined their fortunes with that of the knights, who in most cases forgot the object of the crusade, and gave themselves up to indolence and debauchery. Sanitary precautions were dispensed with on the march, and the result was that wherever the crusaders went they left sickness and pestilence in their wake.