Continent. _There_
was present a population many elements of which sympathised with him and
with the French revolutionary effort. Finally, the allied force in Belgium
was the least homogeneous of the forces with which he would have to deal
in the long succession of struggle from which even a success at this
moment would not spare him.

From all these causes combined, and for the further reason that Paris was
most immediately threatened from this neighbouring Belgian frontier, it
was upon that frontier that Napoleon determined to cast his spear. It was
upon the 5th of June that the first order was sent out for the
concentration of this army for the invasion of Belgium.

In ten days the 124,000 men, with their 370 guns, were massed upon the
line between Maubeuge and Philippeville, immediately upon the frontier,
and ready to cross it. The way in which the frontier was passed and the
river Sambre crossed before the first actions took place form between them
the preliminaries of the campaign, and must be the subject of my next
section.

II

THE PRELIMINARIES: NAPOLEON'S ADVANCE ACROSS THE SAMBRE

To understand the battle of Waterloo it is necessary, more perhaps than in
the case of any other great decisive action, to read it strategically:
that is, to regard the final struggle of Sunday the 18th of June as only
the climax of certain general movements, the first phase of which was the
concentration of the French Army of the North, and the second the passage
of the Sambre river and the attack. This second phase covered four days in
time, and in space an advance of nearly forty miles.

There is a sense, of course, in which it is true of every battle that its
result is closely connected with the strategy which led up to its tactical
features: how the opposing forces arrived upon the field, in what
condition, and in what disposition and at what time, with what advantage
or disadvantage, is always necessarily connected with the history of the
campaign rather than of the individual action; but, as we saw in the case
of Blenheim, and as might be exemplified from a hundred other cases, the
greater part of battles can be understood by following the tactical
dispositions upon the field. They are won or lost, in the main, according
to those dispositions.

With Waterloo it was not so. Waterloo was lost by Napoleon, won by the
Allies, _not_ mainly on account of tactical movements upon the field
itself, but mainly on accou