Valery, which was
actually _twenty_ miles from Oisemont by the nearest roads!

(3) We know that the traitor was captured at Mons, which, if Edward
had been at Oisemont, would have meant that someone had not only
caught him at that great distance from Oisemont, but had brought him
back (a total ride of twenty-four miles) without previous knowledge
that he was capable of the valuable information he only gave later
and after offers.

(4) There is no contemporary mention of Oisemont, but we do
positively know from contemporary evidence that the King's household
was, and had been for three days, at Acheux.

Now all this combined is quite conclusive. Oisemont is impossible.
Boismont satisfies every part of the evidence. An hour's riding from
it permits the attack on St Valery. Mons, where the traitor comes
from, is only two miles off; the march from Boismont to the Ford is
just such an advance as would take the dawn and sunrise of a
day--whereas the advance from Oisemont, impossible for all those
other reasons, would involve fourteen to fifteen miles of marching,
and is utterly incompatible with the idea of two or possibly three
heavy fights, and the long march succeeding it.

One last piece of evidence would be conclusive even if we had not all
the rest. There is contemporary record of the Mayor of Abbeville
watching from the heights of Caubert Hill the English army streaming
northward to concentrate round the advanced position of the King.
From that height such an advance could be discerned crossing the
plateau which leads to Acheux, to Mons, and to Boismont. You could no
more see a concentration on Oisemont from it than you could see a
concentration on Greenwich from Camden Hill.

[Illustration: Sketch showing Estuary of the Somme at BLANCHETAQUE in
1346]

III

THE PRELIMINARIES OF THE BATTLE

The manoeuvres of the French and English armies preliminary to the
Battle of Crecy are so instructive upon many points, involved movements so
hazardous and so complex, gave rise to so sharp a series of engagements,
and form in general so large a part of our subject, that they merit a far
larger study than do the approaches to most battles.

They illustrate the comparative lack of thought-out plan which
characterised medieval warfare; they afford a contrast between the compact
and