One of the most significant events in the whole history of our civilization is the rapid increase in population of a number of towns at the beginning of the sixteenth century. During the sixteenth century the number of cities with 100,000 inhabitants and over increased to thirteen or fourteen. During the seventeenth century a few of the formerly large cities decreased in population. The sketch of the social structure of the city in the early capitalistic epoch finds unequivocal corroboration in the numerous "city theories" of the eighteenth century. Since the end of the seventeenth century and the beginning of the eighteenth century, a new element appeared as a city builder, the creditors of the state and the big financiers. The largest cities have attained that degree of expansion because they were the residence of the largest number of great consumers.