Julius Caesar was appointed Proconsul for the combined provinces of Illyricum, Cisalpine and Transalpine Gaul - a vast teritory for him to rule, but still not quite enough. Fortunantely, he commanded one of the best armies of the day, tough veteran legionaries with good military engineering skills. All was going well until 54 BC when a revolt broke out led by Vercingetorix, an Avernian aristocrat. Thrown temporarily onto the back foot, Caesar was forced to react to the Gaul and his attacks, rather than the other way arround. The Gauls annihilated one of his legions in the winter of 54-53 BC, and disaster never seemed far away. The rebelious Gauls were proving to be a huge problem.
In 52 BC the Gauls and Romans met at Gergovia, a fortified hilltop fort.
A Gallic forward position which allowed access to food and water was seized by Caesar in a night raid. Two legions were stationed there and a line of circumvallation were drawn up to starve Gergovia into submission. At this point, Vercingetorix had convinced to Aeduans guarding Caesar's supply line to turn against the Romans. This uprising was put down, but when Caesar was away the Gauls attempted to retake their forward position, and the two legions were hard-pressed to keep them at bay. Although the sortie was thwarted, the Gauls had achieved a much more favourable position. Caesar determined that the only way to take Gergovia was by forcing the Gauls to live their position of strength.
To that end, a legion, as well as other non-combatants were sent to the rear of the fort as a decoy force. The Gauls responded by moving the bulk of their force to watch the rear. Caesar took this opportunity to move to better ground, seizing three Gallic camps. He then ordered a feigned retreat to pull him off the high ground. However, most of the army did not hear this command, and spurred on by their earlier successes, attempted to assault Gergovia, with the exception of the Tenth Legion. The noise of the assault drew the main Gallic army back to the town, and the Roman assault was defeated. The Tenth Legion acted in a rearguard role to prevent a rout. The Gallic pursuit was withdrawn when Vercingetorix saw that the Roman rearguard now had the terrain on their side. 46 centurions and 700 legionaries were killed.
Caesar chastised his legionaries for arrogance and drew them up the next day to challenge to Gauls to battle. However, the Gauls refused to emerge, except for a few cavalry skirmishes, and Caesar was forced to withdraw.
Probably as a result of this victory, the Aedui, who had been allies of Rome, turned against them and sided with Vercingetorix, who was elected as commander in chief of all the Gallic tribes, essentially, king over the Gallic tribes.