Vercingetorix attempted to prevent it from crossing to the left bank of the Allier, but Caesar overreached him and after some days stood before the Arvernian capital Gergovia.( 48) Vercingetorix, however, doubtless even while he was confronting Caesar on the Allier, had caused sufficient stores to be collected in Gergovia and a fixed camp provided with strong stone ramparts to be constructed for his troops in front of the walls of the town, which was situated on the summit of a pretty steep hill; and, as he had a sufficient start, he arrived before Caesar at Gergovia and awaited the attack in the fortified camp under the wall of the fortress.

Caesar with his comparatively weak army could neither regularly besiege the place nor even sufficiently blockade it; he pitched his camp below the rising ground occupied by Vercingetorix, and was compelled to preserve an attitude as inactive as his opponent.

It was almost a victory for the insurgents, that Caesar's career of advance from triumph to triumph had been suddenly checked on the Seine as on the Allier.
In fact the consequences of this check for Caesar were almost equivalent to those of a defeat.
The Haedui Waver The Haedui, who had hitherto continued vacillating, now made preparations in earnest to join the patriotic party; the body of men, whom Caesar had ordered to Gergovia, had on the march been induced by its officers to declare for the insurgents; at the same time they had begun in the canton itself to plunder and kill the Romans settled there.

Caesar, who had gone with two-thirds of the blockading army to meet that corps of the Haedui which was being brought up to Gergovia, had by his sudden appearance recalled it to nominal obedience; but it was more than ever a hollow and fragile relation, the continuance of which had been almost too dearly purchased by the great peril of the two legions left behind in front of Gergovia.

For Vercingetorix, rapidly and resolutely availing himself of Caesar's departure, had during his absence made an attack on them, which had wellnigh ended in their being overpowered, and the Roman camp being taken by storm.
Caesar's unrivalled celerity alone averted a second catastrophe like that of Aduatuca.