Cæsar approved of the resolution taken by Labienus, although it reduced to two the three legions on which he counted; and, although their effective force did not amount to more than 7,000 men, as the safety of the army depended on the celerity of his movements, he proceeded by forced marches to the country of the Nervii; there he learnt from prisoners the perilous situation of Cicero. He immediately engaged, by the promise of great recompenses, a Gaulish horseman to carry a letter to him: it was written in Greek,[438] in order that the enemy, if he intercepted it, might not know its meaning. Further, in case the Gaul could not penetrate to Cicero, he had directed him to attach the letter to the _amentum_ (see page 37, note 2) of his javelin, and throw it over the retrenchments. Cæsar wrote that he was approaching in great haste with his legions, and he exhorted Cicero to persevere in his energetic defence. According to Polyænus, the despatch contained these words: θαῥῥεἱν βοἡθειαν προσδἑχου (“Courage! expect succour”).[439] As soon as he arrived near the camp, the Gaul, not daring to penetrate to it, did as Cæsar had directed him. By chance his javelin remained two days stuck in a tower. It was only on the third that it was seen and carried to Cicero. The letter, read in the presence of the assembled soldiers, excited transports of joy. Soon afterwards they perceived in the distance the smoke of burning habitations, which announced the approach of the army of succour. At that moment, after a five days’ march, it had arrived within twenty kilomètres of Charleroi, near Binche, where it encamped. The Gauls, when they were informed of it by their scouts, raised the siege, and then, to the number of about 60,000, marched to meet the legions. Cicero, thus liberated, sent another Gaul to announce to Cæsar that the enemy were turning all their forces against him. At this news, received towards the middle of the night, Cæsar informed his soldiers, and strengthened them in their desire of vengeance. At daybreak next day he raised his camp. After advancing four miles, he perceived a crowd of enemies on the other side of a great valley traversed by the stream of the Haine.[440] Cæsar did not consider it prudent to descend into the valley to engage in combat against so great a number of troops. Moreover, Cicero once rescued, there was no need for hurrying his march; he therefore halted, and chose a good position for retrenching--mount Sainte-Aldegonde. Although his camp, containing hardly 7,000 men, without baggage, was necessarily of limited extent, he diminished it as much as possible by giving less width to the streets, in order to deceive the enemy as to his real strength. At the same time he sent out scouts to ascertain the best place for crossing the valley.