front of his own house.[36] As a general rule, the heights in Rome were occupied by the better class of residents, and the hollows by the lower stratum of population. This was not indeed entirely so, for poor people no doubt lived on the Aventine, the Caelian, and parts of the Esquiline. But the Palatine was certainly an aristocratic quarter; the Carinae, the height looking down on the hollow where the Colosseum now stands, had many good houses, e.g. those of Pompeius and of Quintus Cicero, and we know of one man of great wealth, Atticus, who lived on the Quirinal.[37] It was in the narrow hollows leading down from these heights to the Forum, such as the Subura between Esquiline and Quirinal, and the Argiletum farther down near the Forum, that we meet in literature what we may call the working classes; the Argiletum, for example, was famous both for its booksellers and its shoemakers,[38] and the Subura is the typical street of tradesmen. And no doubt the big lodging-houses in which the lower classes dwelt were to be found in all parts of Rome, except the strictly aristocratic districts like the Palatine. The whole free population may roughly be divided into three classes, of which the first two, constituting together the social aristocracy, were a mere handful in number compared with the third. At the top of the social order was the governing class, or _ordo senatorius_: then came the _ordo equester_, comprising all the men of business, bankers, money-lenders, and merchants (_negotiatores_) or contractors for the raising of taxes and many other purposes (_publicani_). Of these two upper classes and their social life we shall see something in later chapters; at present we are concerned with the "masses," at least 320,000 in number,[39] and the social problems which their existence presented, or ought to have presented, to an intelligent Roman statesman of Cicero's time.