In the winter preparations were made on a large scale for a second crossing, a large body of transports being prepared and collected at Portus Itius (perhaps Wissant, near Cape Grinez). The troops in the meantime were carefully trained in handling newly constructed vessels specially planned for the waters of the narrow seas. During the winter the periodic signs of disaffection among the Gauls were again plainly visible, this time the Treviri were intriguing with the Germans. An advance in force from Cæsar was needed to put a check to the rising hopes of the anti-Roman party, whose chief, Indutiomar, was forced to give hostages for his good behavior. Much discontent was caused by the necessity of sending contingents to the army; besides, the legions were a burden on the food supplies of the land. The feeling against foreign control grew so strong that Cæsar determined to take some of the Gallic chiefs with him to Britain, to keep them under personal observation. Dumnorix, the Æduan, tried to secure common action among all and to induce the other chiefs not to embark. Only Dumnorix, however, withdrew when the fleet was about to sail. A party was sent back to pursue him. When he resisted, he was slain. The second expedition to Britain was on an unprecedented scale. There were five legions, two cavalry troops, and an armada of 800 vessels to carry them. The British tribes withdrew from the coast, and there was some fighting, as the Romans made their way inland to attack various British strongholds. Some of the tribes submitted, but the Roman victories were more apparent than real; the camp around the fleet was attacked, and as the army returned, it was continually harassed by an active enemy, who dogged each stage of the march, but refused to come out and fight in the open. The chief result of the invasion was the collection of reliable information about the people and their customs. The island was not occupied or formally conquered for nearly a century. The captives that were taken were brought over to the continent and sold as slaves. (54 B.C.) When the expedition returned, the troops were distributed through Gaul in winter quarters as camps of observation, not more than a hundred miles from one another; Cæsar’s own headquarters being at Amiens. The scene of the first disturbance was in the northeast; a Roman garrison on the march from one camp to another was cut off, and only a few stragglers were left to tell the tale. Cicero’s brother Quintus, the commander of another garrison, was attacked, and no message could be got through the hostile tribes of the Nervii to tell Cæsar of his desperate straits. Finally news was carried by means of a Gallic slave whose master, a Nervian refugee, promised him his liberty if he were successful.