than that embraced by the city wall; and just as new walls covering
larger territory could be built for the city, so a new _pomerium_ line
could be drawn. As was becoming for a spiritual barrier there was
nothing to mark it except the boundary stones through which the
imaginary line passed. The wall, which Servius built and which continued
to be the outer wall of Rome for a period of eight or nine hundred years
until the third Christian century, was at the time of its building
coincident in the main with the line of the _pomerium_, with one very
important exception: namely that all the region of the Aventine, which
was inside the limits of the political city and embraced by the Servian
wall, lay outside the _pomerium_ line and was in other words outside the
religious city. It continued thus all through the republic and into the
empire until the reign of Claudius. Originally the _pomerium_ line
played an important part in the religious world and it continued to do
so until the middle of the republic, during the Second Punic War, when
its sanctity was destroyed and it lost its real religious significance,
though it remained as a formal institution. As a divine barrier it
served originally in the world of the gods very much the same purpose as
the material wall of stone did in the world of men. Before the problem
of foreign gods had begun to exist for the Romans, in the good old days
when they knew only the gods of their own religion, the _pomerium_
served to keep within the bounds of Rome all the beneficent kindly gods
whose presence was not needed outside in the fields, and it served fully
as important a purpose in keeping outside of Rome the gods who were
feared rather than loved, for example the dread war-god Mars. When
foreign gods began to be introduced into Rome they might, of course, be
worshipped inside the _pomerium_ by private individuals, but when the
state acknowledged them it was more prudent that her worship should be
outside the sacred wall. Thus it came to pass that the foreign gods, who
were taken into the cult of the Roman state, were given temples in the