invasion, for in fact bands of insurgents
had already shown themselves in the territory of the Helvii
on the south slope of the Cevennes. Alesia lay almost on his way;
the cavalry of the Celts, the only arm with which Vercingetorix
chose to operate, attacked him on the route, but to the surprise
of all was worsted by the new German squadrons of Caesar
and the Roman infantry drawn up in support of them.

Caesar in Front of Alesia
Siege of Alesia

Vercingetorix hastened the more to shut himself up in Alesia;
and if Caesar was not disposed altogether to renounce the offensive,
no course was left to him but for the third time in this campaign
to proceed by way of attack with a far weaker force against an army
encamped under a well-garrisoned and well-provisioned fortress
and supplied with immense masses of cavalry. But, while the Celts
had hitherto been opposed by only a part of the Roman legions,
the whole forces of Caesar were united in the lines round Alesia,
and Vercingetorix did not succeed, as he had succeeded at Avaricum
and Gergovia, in placing his infantry under the protection of the walls
of the fortress and keeping his external communications open
for his own benefit by his cavalry, while he interrupted those
of the enemy. The Celtic cavalry, already discouraged by that defeat
inflicted on them by their lightly esteemed opponents, was beaten
by Caesar's German horse in every encounter. The line
of circumvallation of the besiegers extending about nine miles
invested the whole town, including the camp attached to it.
Vercingetorix had been prepared for a struggle under the walls,
but not for being besieged in Alesia; in that point of view
the accumulated stores, considerable as they were, were yet
far from sufficient for his army--which was said to amount to 80,000
infantry and 15,000 cavalry--and for the numerous inhabitants
of the town. Vercingetorix could not but perceive that his plan
of warfare had on this occasion turned to his own destruction,
and that he was lost unless the whole nation hastened up to the rescue
of its blockaded general. The existing provisions were still,
when the Roman circumvallation was closed, sufficient for a month
and perhaps something more; at the last moment, when there was still
free passage at least for horsemen, Vercingetorix dismissed
his whole cavalry, and sent at the same time to the heads
of the nation instructions to call out all their forces and lead them
to the