He didn't want to leave any enemies behind him who might get in the way of the grain deliveries and supply. The siege lasted three days before a deputation was sent out to discuss terms of surrender. Once this was finalized, Caesar set off again for Gorgobina via Cenabum. The Carnute had only just heard of the siege at Vellaundunum. They had begun to gather and organize troops to garrison Cenabum, the Carnutes stronghold. They didn't expect the siege to be so short and were surprised to find Caesar camped outside the town. They decided to escape over the bridge at the back but Caesar had predicted this and stationed patrols to keep armed watch all night. When he heard of the escape, he set fire to the gates of the oppidum and entered. Because the bridge and roads were so narrow, very few inhabitants escaped. The Capture of Bourges
Because of his losses at Cenabum, Vellaunodunum, and also Noviodunum, Vercingetorix decided to call a council of war to decide what to do next. He suggested that they put all their efforts into trying to cut off the Romans' supplies of grain and fodder. He also thought it would be a good idea to burn all villages and isolated buildings in any direction from the Romans' line of march. Because of the season, the grass at the moment was impossible to cut and so the Romans would have to send small patrols to try and forage for food. This would mean the Gauls could, daily, pick them off easily. He later suggested that, because of the way in which the Romans easily destroyed the oppida, it would be a good idea to burn all oppida that were not absolutely safe. The others at the council agreed unanimously. Within a day, 20 Bituriges towns were on fire and the other tribes followed suite. The countryside was ablaze. It hurt a lot of the Gauls to burn their strongholds but in the case of the Bituriges, it was too much to bare. They refused to set fire to Bourges saying it was the most beautiful town in the country and that it was fairly well protected, surrounded by marsh and forests, it would be easy to defend. After much begging and pleading, Vercingetorix agreed and sent special troops to defend it. He set up camp about 16 miles from Bourges. Caesar had arrived and was camped at a small gap between the marsh and forests. he had built a siege-terrace but could do little else because of the awkward terrain. He was trying to negotiate with the Aedui and the Boii to provide him with grain. the Aedui were reluctant and, while the Boii were willing to provide the grain, they were a small weak tribe and couldn't support the full army.