V. The Saône, which crossed the countries of the Ædui and the Sequani,[177] flowed, then as now, in certain places with an extreme sluggishness. Cæsar says that people could not distinguish the direction of the current. The Helvetii, who had not learned to make bridges, crossed the river, between Trévoux and Villefranche, on rafts and boats joined together. As soon as the Roman general had ascertained by his scouts that three-quarters of the barbarians were on the other side of the river, and the others were still on his side, he left his camp towards midnight (_de tertia vigilia_) (_see note 1 on page 69_) with three legions, came upon those of the Helvetii who were still on the left bank, to the north of Trévoux, in the valley of the Formans, towards six o’clock in the morning, after a march of eighteen kilomètres, attacked them by surprise in the midst of the confusion of passing the river, and slew a great number. Those who could escape dispersed, and concealed themselves in the neighbouring forests. This disaster fell upon the Tigurini (_the inhabitants of the Cantons of Vaud, Friburg, and a part of the Canton of Berne_), one of the four tribes of which the nation of the Helvetii was composed, the same which, in an expedition out of Helvetia, had formerly slain the Consul L. Cassius, and made his army pass under the yoke.[178] After this combat, Cæsar, in order to pursue the other part of the enemy’s army, and prevent its marching towards the south, threw a bridge across the Saône, and transported his troops to the right bank. The barques which followed him for the conveyance of provisions would necessarily facilitate this operation. It is probable that a detachment established in the defiles on the right bank of the Saône, at the spot where Lyons now stands, intercepted the road which would have conducted the Helvetii towards the Roman province. As to the three legions which remained in the camp of Sathonay, they soon rejoined Cæsar. The Helvetii, struck by his sudden approach, and by the rapidity with which he had effected, in one single day, a passage which had cost them twenty days’ labour, sent him a deputation, the chief of which, old Divico, had commanded in the wars against Cassius. In language full of boast and threatening, Divico reminded Cæsar of the humiliation inflicted formerly on the Roman arms. The proconsul replied that he was not forgetful of old affronts, but that recent injuries were sufficient motives for his conduct. Nevertheless, he offered peace, on condition that they should give him hostages. “The Helvetii,” replied Divico, “have learned from their ancestors to receive, but not to give, hostages; the Romans ought to know that.” This proud reply closed the interview.