Following this rout Drappes, of Senon, at the head of a troop of 2000 to 5000 unsworn men, was joined by the Cadurcian Lucterios, an escapee from Alesia. They decided to invade Provincia (the region of Narbonne). The legate Caninius pursued them with two legions. When the Romans were about to overtake them, the Gauls took refuge on the oppidum (hill fort) of Uxellodunum in the land of the Cadurques (later known as Quercy).
On reaching Uxellodunum, Caninius established three camps on high ground nearby and undertook the construction of a ditch (contrevallation) to circle the oppidum.
Drappes and Lucterios established their camp ten miles from Uxellodunum. In this way they could harass the Romans and comb the region for supplies of wheat for their troops. One night, after gathering sufficient provisions, Lucterios was leading a convoy of wheat when he was intercepted by Caninius and was forced to flee. Using information extracted from the captured Gauls, the Romans then made a surpise attack on Drappes' camp, massacred his army and took him prisoner.
The most surprising aspect of this story is that, despite having lost their principal leaders, the Gauls continued the fierce battle. They held their own against Caninius and against Fabius who had arrived with reinforcements of two and a half legions.
Caninius was obliged to give an explanation to Caesar, who had arrived unexpectedly with his cavalry, followed by the two legions of Calenus.
Seeing that the Roman fortifications completely encircled the place, Caesar decided to deprive the Gauls of water. Their access to the river was made impossible by the machines of war and, just downstream from the water source, which bubbled from the foot of the ramparts, Caesar ordered to be built an 18m high embankment topped with a tower of 10 levels (27 metres high), constructed to prevent the Gauls getting fresh water supplies.
These works were a lure, a diversion, because Caesar had another plan: to dig tunnels out of view of the defenders to dry up the springs. Despite violent battles and the burning of the tower, the Roman sappers achieved their goal. The Gauls, deprived of water, believed themselves abandoned by their gods and capitulated.
Caesar was pitiless. The hands of all those who had carried weapons were cut off, but their lives were spared. This unusual cruelty was meant as an example to others, to prevent any further insurrection. The impending date of 1st March, 50 BC marked the end of Caesar's time as a proconsul and he wanted to return victoriously to Rome. A "horde of brigands" had almost put the rest of his political career in peril. The combat in 51 BC lasted around two months, from mid July to mid September.