Although he did not venture to follow the fugitives, they sent ambassadors, accompanied by Commius, whom the Britons released from prison and chains, to sue for peace. The victor complained, and with some show of justice, of the reception he had met with, after they had sent envoys to him in Gaul with offers of submission, and also of the arrest of his ambassador; and lamented the blood that had been shed. To this harangue the Britons artfully replied that they had imprisoned Commius in order to preserve him from the fury of the people, and with this excuse Cæsar either was, or affected to be, content. He granted the peace they came to solicit, and demanded hostages, which were promised, for the future. A storm dispersed the eighteen galleys which were to transport the cavalry of Cæsar, and drove them back upon the coast of Gaul. This was not the only misfortune the Romans endured. That same night the moon was at its full; it was the season of the equinox, and the tide rose to an unusual height, filling the vessels which Cæsar had drawn out of the reach of danger, as he imagined, on the sands. The larger ships, which had served him as a means of transport, were driven from their anchors, and many of them wrecked. Although perfectly aware of the perils which menaced their invaders, the Britons appear to have proceeded with the utmost caution. Whilst a league was secretly being formed to crush the Romans, their chiefs appeared daily in their camp, professing unbroken friendship. Suddenly they fell upon the seventh legion, which had been sent to a distance to forage. The plan was well contrived to defeat the enemy in detail. Many of their leaders remained in camp, in order to lull suspicion, whilst their confederates surprised the Romans, who, having laid aside their arms, were soon surrounded, and must have been cut off but for the timely arrival of Cæsar, who, warned by his outposts that a cloud of dust thicker than usual had been seen at a distance, guessed immediately what had occurred. With a portion of his army he fell upon the assailants, and, after a desperate struggle, disengaged the threatened legion, and returned with it to the camp in safety. The lesson was a sharp one, and the rains soon afterwards setting in, the invader did not attempt to renew the battle.