is likely that a
good part of this space was long unoccupied by houses, and served to
shelter the cattle of the farmers living outside, when an enemy was
threatening attack. But in Cicero's time, as to-day, all this space
was covered with dwellings; and as the centre of the city came to be
occupied with public buildings, erected on sites often bought from
private owners, the houses were gradually pushed out along the roads
beyond the walls. Exactly the same process has been going on for
centuries in the University city of Oxford where the erection of
colleges gradually absorbed the best sites within the old walls, so
that many of the dwelling-houses are now quite two miles from the
centre of the city. The fact is attested for Rome by the famous
municipal law of Julius Caesar, which directs that for a mile outside
the gates every resident is to look after the repair of the road in
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