As the campaign year of 56 BC opened, Caesar found that Gaul still wasn't quite ready for Roman occupation. In his own words: "he reflected that almost all the Gauls were fond of revolution, and easily and quickly excited to war; that all men likewise, by nature, love liberty and hate the condition of slavery, he thought he ought to divide and more widely distribute his army, before more states should join the confederation." Labienus was sent with the bulk of the cavalry among the Treveri which was near the Rhine. He was charged with keeping peace among the Belgae and preventing Germanic crossings into Gallic territory.
P. Crassus was sent to Aquitania with 12 legionary cohorts to subdue the tribes there. With the help of Gallic auxilia, as in all cases, Crassus quickly brought Roman control to the westernmost portion of Gaul. Though with some difficulty, Crassus won two decisive battles over the Sotiates followed by the Cantabri. When word passed through the region of the Roman victories, it encouraged the rest of the region to surrender peacefully. In short order, the Tarbelli, Bigerriones, Preciani, Vocasates, Tarusates, Elurates, Garites, Ausci, Garumni, Sibuzates and Cocosates surrendered to Roman domination.
In the north, Caesar ordered Q. Titurius Sabinus with 3 legions to quell any potential opposition among the Unelli, Curiosolitae, and the Lexovii. Sabinus made short work of any resistance and brought his territory under Caesar's sway. Decimus Brutus, the young future assassin of Caesar, was sent to build a fleet amongst the Veneti. This move, while certainly designed to establish authority over the whole of Gaul, was a certain precursor to the invasion of Britain. The Veneti controlled the waterways with a formidable fleet of their own and were augmented by British Celts. At first the Gallic vessels outmatched the Romans, and Brutus could do little to hamper Veneti operations. Roman ingenuity took over, however, and they began using hooks launched by archers to grapple the Veneti ships to their own. Before long, the Veneti were completely defeated, and like many tribes before them, sold into slavery.
With the defeat of the Gallic resistance, Caesar next began to focus his attention across the channel. Still, the conquest was not quite as complete as it seemed. First Caesar would have to deal with more Germanic incursions before he could cross to Britain. And despite his confidence, the Gallic tribes were not nearly as subdued as he thought. For now, though, Caesar returned to Cisalpine Gaul to attend to political matters in Rome.