a zone of debateable land. On both sides some temporary
intrusion upon or occupation of country held by a neighbour, which
would now be the signal for mobilising an army, was treated as a
trespass of small importance, to be resented and rectified at leisure.
It is true that in earlier times the Romans marked off distinct
frontiers, and guarded them by military posts; but their policy was to
acknowledge no frontier power with equal rights, and their actual
political jurisdiction usually extended far beyond their lines of
defence, which were advanced or withdrawn as political or military
considerations might require. In fact, the Roman empire, like the
British empire in Asia, was a great organised State, surrounded, for
the most part, by small and weak principalities, or by warlike tribal
communities, and it grew by a natural process of inevitable expansion.
The emperors were often reluctant to enlarge their possessions; but
the raids and incursions of intractable barbarians, or the revolt of
some protected chiefship, frequently left them no option but to
conquer and annex. They soon found themselves compelled to overstep
the limits of empire prescribed by the policy of Augustus, and to lay
down an advanced frontier in the lands beyond the Rhine and the
Danube.

In Europe, where, as we have said, all national frontiers are now
fixed and registered, the position of a civilised government entangled
in chronic border warfare has long been unknown; the tradition of such
a state of things is preserved in popular recollection mainly by local
records and old ballads. Yet for Englishmen the subject possesses
peculiar interest, since it is connected with their earlier history;
and moreover our dominion in India invests it with special importance,
for it is there a matter of immediate experience and active concern.
We may recollect, in the first place, that Britain was an outlying
province of the Roman empire, for at this moment we are excavating the
ruins of the wall built by the Romans to protect their northern
frontier from the incursions of the warlike tribes beyond it, by the
first administration that established, for a time, peace and
civilisation in England. Then, in the middle ages, and long
afterwards, the border between the kingdoms of England and Scotland
which ran northward of the old Roman line, was for centuries the scene
of plundering raids, punitive expeditions, and internecine feuds that
often laid waste the count