The siege of Cenabum (early 52 B.C.) was the second of three Roman attacks on Gallic towns that forced Vercingetorix to abandon his siege of Gorgobina, and that saw the Romans capture the town where the great Gallic revolt had begun.
Cenabum (or Genabum) was a Carnute city that had also become a centre of the grain trade. The town was rebuilt by Aurelian in 273-274 and renamed Aurelianum or Aureliani, and this name slowly evolved into its modern name, Orléans. The start of the great Gallic revolt was signalled by a massacre of the Roman inhabitants of the town, amongst them a number of prominent merchants, and an overseer appointed by Caesar.
The rebels had hoped to prevent Caesar from rejoining his legions in their winter quarters in the north of Gaul, but Caesar had moved too fast for them. Once Vercingetorix discovered that Caesar had joined his legions, the Gallic leader decided to attack Gorgobina. This town had been settled by the Boii in 58 B.C. with Caesar's approval. Caesar realised that if he let Gorgobina fall to the rebels then he would lose much of his credibility with his allies. Leaving two legions at Sens (Agendicum) Caesar advanced south to Vellaunodunum, in the lands of the Senones, which fell to him after only three days.
Leaving Caius Trebonius to carry out the terms of the surrender Caesar set out on a rapid march to Cenabum, hoping to capture the town before the Carnutes could get a garrison into the place. Once again the ability of the Romans to move with great speed caught the Gauls out. The Carnutes were indeed preparing to defend Cenabum, but they had expected Vellaunodunum to hold out for much longer. Caesar reached Cenabum late on the second day of his march, only four or five days after he had arrived at Vellaunodunum.
The Romans reached Cenabum too late in the day to attack the town. Caesar placed most of his army in a camp outside the town, but also sent two legions onto the opposite bank of the Loire to prevent the inhabitants escaping over a bridge across the river. The Romans prepared to attack the town on the following day.
During the night the inhabitants of Cenabum attempted to escape across the bridge. Caesar was prepared for this. The legions had been ordered to spend the night under arms. When the inhabitants attempted to leave the town the Romans set the town gates on fire. Hemmed in by the fire and the narrow bridge leaving the city almost the entire population was forced to surrender.
Having captured the town Caesar allowed his men to pillage and burn the town, and to keep what they found, in revenge for the massacre at the start of the revolt. The Romans then crossed the Loire and marched towards Noviodunum, in the lands of the Bituriges.
By this time news of Caesar's movements had reached Vercingetorix. He was forced to abandon the siege of Gorgobina and moved towards Noviodunum in an attempt to prevent the Romans from capturing the town. Vercingetorix's relief force arrived just too late to make any difference at Noviodunum, although there was a minor cavalry battle between the Gallic horse and Caesar's new German auxiliaries, before the Romans moved on to besiege Avaricum, in what developed into the first really major clash of the revolt.