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 relief of Alesia.

He himself, resolved to bear in person the responsibility for the plan of war which he had projected and which had miscarried, remained in the fortress, to share in good or evil the fate of his followers.

But Caesar made up his mind at once to besiege and to be besieged.

He prepared his line of circumvallation for defence also on its outer side, and furnished himself with provisions for a longer period.

The days passed; they had no longer a boll of grain in the fortress, and they were obliged to drive out the unhappy inhabitants of the town to perish miserably between the entrenchments of the Celts and of the Romans, pitilessly rejected by both.
Attempt at Relief Conflicts before Alesia At the last hour there appeared behind Caesar's lines the interminable array of the Celto-Belgic relieving array, said to amount to 250,000 infantry and 8000 cavalry, from the Channel to the Cevennes the insurgent cantons had strained every nerve to rescue the flower of their patriots and the general of their choice--the Bellovaci alone had answered that they were doubtless disposed to fight against the Romans, but not beyond their own bounds.
The first assault, which the besieged of Alesia and the relieving troops without made on the Roman double line, was repulsed; but, when after a day's rest it was repeated, the Celts succeeded--at a spot where the line of circumvallation ran over the slope of a hill and could be assailed from the height above-- in filling up the trenches and hurling the defenders down from the rampart.