All this time Rome had been growing both in her influence and her dominions, when for a while her very existence was threatened by the sudden invasion of seventy thousand Gauls, who poured in from the north. They were defeated in a hard-fought battle and beaten back, but the struggle with the barbarians was long and fierce, and Rome remained exhausted. Her attention was occupied with measures needful for her own defence and in raising both men and money, and except for warning the Carthaginians not to cross the Ebro, she left them for a time pretty much to themselves, thinking vainly that, as long as her navy gave her command of the sea, she had no need to trouble herself about affairs in Spain or Africa. Indeed, after the severe strain of the Gallic war, the Roman senate thought that they were in so little danger either from Carthage or from Greece that their troops might take a sorely needed rest, and the army was disbanded. This was Hannibal's chance, and with the siege and fall of the Spanish town of Saguntum in 218 B.C. began the second Punic war. * * * * * For years the young general had been secretly brooding over his plans, and had prepared friends for himself all along the difficult way his army would have to march. Unknown to Rome, he had received promises of help from most of the tribes in what is now the province of Catalonia, from Philip of Macedon, ruler in the kingdom of Alexander the Great, and from some of the Gauls near the Rhone and along the valley of the Po. Many of these proved broken reeds at the time of trial, when their help was most needed, and even turned into enemies, and Hannibal was too wise not to have foreseen that this might happen. Still, for the moment all seemed going as he wished; war was declared, and Rome made ready her fleet for the attack by sea which she felt was certain to follow. In our days of telephones and telegrams and wireless telegraphy, it is very nearly _impossible_ for us to understand how an army of ninety thousand foot, twelve thousand horse, and thirty-seven elephants could go right through Spain from Carthagena in the south-east to the Pyrenees in the north, and even beyond them, without a whisper of the fact reaching an enemy across the sea. Yet this is what actually occurred. Rome sent a large force under one consul into Sicily, the troops were later to embark for Carthage, another to the Po to hold the Gauls in check, while a third, under Publius Scipio, was shortly to sail for Spain and there give battle to the Carthaginians. That Hannibal was fighting his way desperately through Catalonia at that very moment they had not the remotest idea. * * * * * Not only did Hannibal lose many of his men in Catalonia, but he was obliged to leave a large body behind, under Hanno, his general, to prevent the Catalans rising behind him, and cutting off his communications with Spain.