_Second Campaign_, B.C. 57.--The following year was occupied with the Belgic war. Alarmed at Caesar's success, the various Belgic tribes which dwelt between the Sequana (_Seine_) and the Rhine, and were the most warlike of all the Gauls, had entered into a confederacy to oppose him, and had raised an army of 300,000 men. Caesar opened the campaign by marching into the country of the Remi, who submitted at his approach. He then crossed the Axona (_Aisne_), and pitched his camp in a strong position on the right bank. The enemy soon began to suffer from want of provisions, and they came to the resolution of breaking up their vast army, and retiring to their own territories. Hitherto Caesar had remained in his intrenchments, but he now broke up from his quarters and resumed the offensive. The Suessiones, the Bellovaci, and Ambiani were subdued in succession, or surrendered of their own accord; but a more formidable task awaited him when he came to the Nervii, the most warlike of all the Belgic tribes. In their country, near the River Sabis (_Sambre_), the Roman army was surprised by the enemy while engaged in fortifying the camp. The attack of the Nervii was so unexpected, that before the Romans could form in rank the enemy was in their midst: the Roman soldiers began to give way, and the battle seemed entirely lost. Caesar freely exposed his own person in the first line of the battle, and discharged alike the duties of a brave soldier and an able general. His exertions and the discipline of the Roman troops at length triumphed, and the Nervii were defeated with such immense slaughter, that out of 60,000 fighting men only 500 remained in the state. When the Senate received the dispatches of Caesar announcing this victory, they decreed a public thanksgiving of fifteen days--a distinction which had never yet been granted to any one. _Third Campaign_, B.C. 56.--In the third campaign Caesar completed the subjugation of Gaul. He conducted in person a naval war against the Veneti, the inhabitants of the modern Brittany, and, by means of his lieutenants, conquered the remaining tribes who still held out. In the later part of the summer Caesar marched against the Morini and Menapii (in the neighborhood of Calais and Boulogne). Thus all Gaul had been apparently reduced to subjection in three years; but the spirit of the people was yet unbroken, and they only waited for an opportunity to rise against their conquerors.