During the siege of Mons, in 1691, the Prince of Orange assembled
his army, and advanced as far as Notre Dame de Halle, making a
demonstration to succor the place. Louis XIV, who commanded the siege
in person, called a council of war to deliberate on what was to be
done in case the Prince of Orange approached. The opinion of Marshal
Luxembourg was to remain within the lines of circumvallation, and that
opinion prevailed.
The marshal laid it down as a principle that, when the besieging army
is not strong enough to defend the whole extent of circumvallation, it
should quit the lines and advance to meet the enemy; but when it is
strong enough to encamp in two lines around a place, that it is better
to profit by a good entrenchment--more especially as by this means the
siege is not interrupted.
In 1658, Marshal Turenne was besieging Dunkirk. He had already opened
the trenches, when the Spanish army, under the orders of the Prince Don
Juan, Condé, and D’Hocquincourt, appeared in sight, and took post upon
the Downs, at a distance of a league from his lines. Turenne had the
superiority in numbers, and he determined to quit his entrenchments.
He had other advantages also. The enemy was without artillery, and
their superiority in cavalry was rendered useless by the unfavorable
nature of the ground. It was, therefore, of great importance to beat
the Spanish army before it had time to entrench itself and bring up its
artillery. The victory gained by the French on this occasion justified
all the combinations of Marshal Turenne.
When Marshal Berwick was laying siege to Philipsburg, in 1733, he had
reason to apprehend that the Prince of Savoy would attack him with
all the forces of the empire before its termination. The marshal,
therefore, after having made his disposition of the troops intended for
the siege, formed, with the rest of his army, a corps of observation to
make head against Prince Eugene, in case the latter should choose to
attack him in his lines, or attempt a diversion on the Moselle or Upper
Rhine. Prince Eugene, having arrived in front of the besieging army,
some general officers were of opinion that it was better not to await
the enemy in the lines, but to move forward and attack him. But Marshal
Berwick, who agreed with the Duke of Luxembourg, that an army which
can occupy, completely, good entrenchments is not liable to be forced,
persisted in remaining within his works. The result proved that this
was also the opinion of Prince Eugene, for he did not dare to attack
the entrenchments, which he would not have failed to do if he had any
hopes of success.