Although the fight at Ticinus was only a skirmish, yet the victory of Hannibal’s cavalry encouraged many Gallic tribes to throw off their fear of Rome and join the Carthaginians. Even those Gauls who had joined the Roman camp were eager to escape, and one night more than two thousand of them mutinied, and, overpowering the sentinels, left the Romans to join Hannibal. After the flight of the Gauls, Scipio thought it would be wise to move to a safer position, so he marched to the upper Trebia, another tributary of the Po. Here he was joined by Sempronius. Hannibal was eager to fight while the Gauls were still faithful to him, for he, as well as the Romans, knew their unstable character. Scipio on the other hand, wished to delay meeting the enemy, for he was still wounded. Moreover, he thought that if a battle did not take place soon, the Gauls would be more than likely to forsake their new ally. But Sempronius, who had entire charge of both the Roman armies since Scipio was wounded, could brook no delay. The Carthaginian general had already discovered that it would be easy to tempt the second Consul to fight. He therefore determined to entice him to cross the river Trebia. It was winter. Heavy rains and sleet had fallen, and the river was flooded, when, early one bleak morning, Hannibal ordered his brave young brother Mago, with a large number of troops, to lie in ambush in a dried-up watercourse, where they were hidden by high banks and tall bushes. Until a signal bade them dash out upon the enemy, they were not to stir. Meanwhile a body of Carthaginian cavalry had been sent across the river, close to the Roman camp. The cavalry was to tempt Sempronius to leave his camp and offer battle. The Consul no sooner saw the enemy, than without waiting for his men to have breakfast, he ordered the horsemen to advance at once, and the infantry to follow as soon as possible. Cold and hungry, the Roman army obeyed, and the Punic cavalry retreated across the river before the enemy. The Roman foot soldiers were ordered to follow, although the water was cold as ice, and reached almost to their shoulders. When they scrambled up on the other bank, they were chilled to the bone as well as faint for want of food. More miserable bedraggled Roman soldiers had never been seen. They were scarcely fit to attack a small body of the enemy, much less to face the main body of the Carthaginian army, which, well fed and warm, awaited them in battle array. Hannibal, with his usual care for his soldiers, had seen that they had a good meal, after which he had bade them rub their bodies with oil in front of the camp fires, before they buckled on their armour. It was soon plain that the Romans were not fit to cope with the comfortable Carthaginian troops. Yet in spite of the elephants, that trampled them underfoot, and in spite, too, of the Punic cavalry which was stronger than their own, the Roman legions held their ground.