am,
just outside the wall, and each reposing on the river.

But in an active time even this precaution fails, and that for two
reasons. First, the growth of the town makes any possible garrison of
the fortress too small for the force with which it might have to cope;
and, secondly, this same growth physically overlaps the exterior
fortress; suburbs grow up beyond the wall, and the castle finds itself
at last embedded in the town. Thus within a hundred and fifty years of
its completion the Louvre was but a residence, wholly surrounded, save
upon the water front, by the packed houses within the new wall of
Marcel.

A tendency therefore arises, more or less early according to local
circumstance, to establish a fortified base within striking distance
of the civilian centre which it is proposed to command; and striking
distance is a day's march. The strict alliance between Paris and the
Crown forbade such an experiment to the Capetian Monarchy, but, even
in that case, the truth of the general military proposition involved
is proved by the power which Montlhery possessed until the middle of
the twelfth century of doing mischief to Paris. In the case of London,
and of a population the wealthier of whom were probably for some years
hostile to the Conqueror, the immediate necessity for an exterior base
presented itself, and though the distance from London was indeed
considerable, Windsor, under the circumstances of that moment, proved
the most suitable point at which to establish the fortress.

Some centuries earlier or later the exact point for fortification
would have lain at _Staines_, and Windsor may be properly regarded as
a sort of second best to Staines.

The great Roman roads continued until the twelfth century to be the
main highways of the barbaric and mediaeval armies. We know, for
instance, from a charter of Westminster's, that Oxford Street was
called, in the last years of the Saxon Dynasty, "Via Militaria," and
it was this road which was still in its continuation the marching road
upon London from the south and west: from Winchester, which was still
in a fashion the capital of England and the seat of the Treasury. Now
Staines marks the spot where this road crossed the river. It was a
"nodal point," commanding at once the main approach to London by land
and the main approach by water.

But there is more than this in favour of Staines. I have already said
that a fortress commanding a civilian population--an anc