After the battle of Alesia and the subsequent surrender of Vercingetorix, little changed in Gaul for Caesar save for one important circumstance. A great number of tribes remained in revolt, but there was no longer a coalition of tribes working together against the Roman presence.
Caesar now had the luxury of dealing with these Gallic tribes on an individual basis. Immediately after Alesia, Caesar marched south into Aedui territory and reaffirmed their allegiance to Rome. The Arverni, Vercingetorix's own tribe, submitted as well and both, despite their leading the revolt and betraying the Roman alliance respectively were treated with honor.
As two major tribes within central Gaul, it was to Caesar's benefit to treat them favorably. After taking advantage of the fall harvest, Caesar scattered his legions throughout Gaul in an attempt to minimize the continuing revolt, and the Senate voted another 20 day festival (3rd in total) of thanks in Caesar's honor.
While wintering in Gaul at Bibracte, the revolt started in full effect once again. Caesar marched to the territory of the Bituriges and brought them to submission within 40 days. Caesar returned to Bibracte by February 51 BC and offered his men 200 sesterces per legionary and 2000 per Centurion as a reward for their continuing sacrifice and hardship. Soon after returning however, the beaten Bituriges were under assault from the Carnutes, and Caesar marched back to their lands again. Decisively routing the Carnutes, the Bellovaci were the next source of trouble. In mid winter, Caesar's allies the Remi were under pressure from these Bellovaci and Caesar marched to the lands of the Seussiones to meet them.
With 4 legions, Caesar met the Gallic army but was unable to lure them into an open battle. Small cavalry engagements weren't decisive either way, and the Gauls did a good job of using guerrilla tactics against Roman foragers. Caesar ordered more of his men to join him in what might seem to be the last major enemy of the long war. Fending off ambush attempts and fighting the cold of winter, the Romans never seemed in serious trouble, but weren't able to bring the issue to a close. Finally, sometime in mid February 51 BC, the Romans met the rebellious Gauls in a major battle. The Gauls tried to ambush a foraging column, but were soundly defeated, and by now Caesar had become merciless. Most remaining tribes now sent hostages to Caesar in a show of loyalty, but a few brave tribes remained at odds.
The lands of former enemy Ambiorix, along the Rhine were burnt and pillages, while Labienus was sent to destroy the Treveri for their involvement in the revolt. Caius Caninius and Caius Fabius were sent to destroy an enemy force near Limonum, killing 12,000 Gauls and capturing a great deal of spoils in the process. The remaining forces retreated to a fort in southwest Gaul called Uxellodunum, and Caesar's legates invested the town in an Alesia like siege. Caesar meanwhile was traveling throughout Gaul with his victorious army as a show of force securing loyalty from the numerous tribes. When word reached him of the situation at Uxellodunum, he marched quickly to make a final example of this last hold out against Roman authority.
The Romans cut off the water supply of the town and let the people die of thirst and starvation. Caesar's great successes left the remaining Gauls believing that their defeat was the will of the gods, and they eventually capitulated. Caesar administered his most ruthless punishment yet, cutting off the hands of all those men who bore arms against Rome. Any remaining resistance within Gaul quickly ended, and Caesar spent the rest of the year 51 BC, assuring the loyalty of the tribes. The legions were once again spread throughout Gaul to prevent further uprisings, but this time all of Gaul was exhausted and had lost the will to fight.
After 8 long years and countless campaigns, the Gallic Wars had finally come to an end. Caesar had proven himself not only as one of the greatest and most brutal conquerors of the ancient world, while also conducting some of the most brilliant siege tactics witnessed by history. He conquered over 350,000 sq. miles of territory, killing over 1 million Gauls and enslaving a likely equal number in the process. Of the original estimated population of 3 to 6 million Gauls, (depending on which numbers are accurate) at best 1/3 of the population was wiped out and at worst only 1/3 remained after the wars of Caesar. He bridged the Rhine not once but twice, and crossed the channel to Britain in an equal manner, becoming the first Roman to accomplish both things.
No Roman had ever accomplished so much, and yet been so brutal to an enemy. Vast amounts of wealth and slaves were brought back to Rome, and Gaul remained from that time on a loyal and generally Romanized province of the growing empire.