ut once such
towns had been established, it would be necessary to connect them
with one another by land routes, and these would be determined
chiefly by the lie of the land. Where mountains interfered, a large
detour would have to be made--as, for example, round the Pyrenees;
if rivers intervened, fords would have to be sought for, and a new
town probably built at the most convenient place of passage. When
once a recognised way had been found between any two places, the
conservative instincts of man would keep it in existence, even
though a better route were afterwards found.

The influence of water communication is of paramount importance
in determining the situation of towns in early times. Towns in
the corners of bays, like Archangel, Riga, Venice, Genoa, Naples,
Tunis, Bassorah, Calcutta, would naturally be the centre-points
of the trade of the bay. On rivers a suitable spot would be where
the tides ended, like London, or at conspicuous bends of a stream,
or at junctures with affluents, as Coblentz or Khartoum. One nearly
always finds important towns at the two ends of a peninsula, like
Hamburg and Lubeck, Venice and Genoa; though for naval purposes
it is desirable to have a station at the head of the peninsula,
to command both arms of the sea, as at Cherbourg, Sevastopol, or
Gibraltar. Roads would then easily be formed across the base of
the peninsula, and to its extreme point.

At first the inhabitants of any single town would regard those
of all others as their enemies, but after a time they would find
it convenient to exchange some of their superfluities for those
of their neighbours, and in this way trade would begin. Markets
would become neutral ground, in which mutual animosities would
be, for a time, laid aside for the common advantage; and it would
often happen that localities on the border line of two states would
be chosen as places for the exchange of goods, ultimately giving
rise to the existence of a fresh town. As commercial intercourse
increased, the very inaccessibility of fortress towns on the heights
would cause them to be neglected for settlements in the valleys or
by the river sides, and, as a rule, roads pick out valleys or level
ground for their natural course. For military purposes, however, it
would sometimes be necessary to depart from the valley routes,
and, as we shall see, the Roman roads paid no regard to these
requirements.

The earliest communication between nations, as we have s