His success in dealing with the Helvetii turned the eyes of all Gaul upon the conqueror. Many tribes then asked his aid against Ariovistus, a German chief who came from across the river Rhine and with his yellow haired followers, clad in the skins of animals, was plundering the Gaulish province. Cæsar, with the quickness that always won him success in battle, advanced against Ariovistus and completely defeated him, driving his men in confusion back across the Rhine to the lands they had come from.
In the following spring there was great danger that all Gaul would revolt to free itself from the control of the Romans. Of all the tribes that were opposed to him, Cæsar considered that the Belgæ, the people who lived in what is now Belgium, were the bravest and the most dangerous enemies against whom he must fight. So he marched against them and placed his legions behind strong fortifications until he could gain a favorable moment to come forth and attack them. The Belgæ tried all sorts of tricks and ruses to draw Cæsar from his position, but they did not succeed in doing this. Then, perhaps because they had not sufficient food, they commenced a retreat back to their own country, from which they had issued to attack Cæsar. On their heels rode the Roman cavalry, who harassed them constantly, darting in and killing stragglers and attacking the rear guard whenever the opportunity offered.
One night, however, when the Romans were about to encamp in some wooded country on the River Sambre, three tribes of the Belgæ fell upon them in a surprise attack that came so swiftly and so violently that the Roman legions were almost routed. Cæsar's force was not wholly composed of Romans, and all the soldiers under his command except the Romans fled pell mell from the field, but the Roman soldiers, in spite of everything, stood firm, displaying the marvelous discipline that had conquered the world, and soon had victory in their grasp. But the Roman soldiers were seldom merciful and scarcely a foeman escaped the slaughter that followed.
That winter Cæsar returned to northern Italy, leaving his legions in Gaul under the command of his lieutenants. In his winter retreat he enjoyed himself and spent enormous sums of money, listening eagerly to news of everything that had taken place in Rome since his departure.