the Battle of Arsouf in 1189, where Richard the Lionheart personally placed each of
his cavalry and infantry units. Should that plan go wrong, or should troops of the
various arms be separated from each other (as, e.g., was always happening during the
battles that the Hellenistic monarchs fought against the Romans, and as also
happened at Hattin in 1187), disaster would stare the commander in the face.
Now, with every corps able to take over from every other almost at a moment’s
notice and wage combined-arms warfare in turn, such planning became unneces-
sary. The result was that, even as the width of the front across which the army
operated grew, that army also made vast gains in flexibility.
Gone were the days when vanguards, flank guards, rearguards, wings, reserves,
and the like had to be put together each time there was a mission to be
accomplished or an engagement fought. Gone, too, were the days when such
bodies of troops, lacking a combination of the three arms, a permanent head-
quarters, and the necessary services, were only able to look after themselves to a
very limited extent and, therefore, had to be kept fairly close to general head-
quarters so as to submit their reports and receive their orders. Instead, contem-
porary wisdom, as exemplified by Clausewitz himself, considered that each corps
should be able to fight independently, even when outnumbered two or three to
one, for long enough to be stationed a day’s march away from its neighbour. 26 As
a result, the width of the front across which an army could safely operate went up
as if by a stroke of magic, from about four miles to several times that number.
Like Athene leaping out of Zeus’ head, all these developments came together
for the first time in the campaign of 1805; as they did so, the world held its breath.
On this occasion, theGrande Arme ́e, as it was known, numbered approximately
170,000 men. Herodotus’ mythological 1,500,000 Persian soldiers apart, this was
probably the largest number that had been brought together for a single cam-
paign in history until that time. They were divided into seven corps, each with its
own Roman number, though, in practice, there was always a tendency to call each
corps after its commander. Having arrived at their jumping-off positions on the
Rhine—some of the corps came from Boulogne, where they had been preparing
to invade England, whereas others came from the Netherlands—they stretched
from Koblenz in the north all the way to Freiburg in the south. The distance
between the wings was about 200 miles. However, since just one corps was
deployed south of Strasbourg, where it acted as a decoy, the average distance
between the six remaining ones amounted to twenty-five miles—exactly as
Clausewitz recommended. Crossing the Rhine on 25–6 September, each corps
marched by a separate road and was assigned a foraging area to its left. 27 Later, as
the campaign unfolded, geographical realities and operational requirements
caused both the distance between the corps and the front as a whole to become
progressively smaller.
From the description so far, one might think that theGrande Arme ́e, propelled
by the emperor’s orders as if by a huge spring, simply formed a phalanx vastly
larger than, but not essentially different from, anything that had been conceived
from the time of Leuctra (371 BC) on. That is the truth, but it is only a half-truth.
What is really impressive about the campaign is both the good order with which it
Napoleon and the Dawn of Operational Warfare 21