War with Rome was what Hannibal most desired. He was pledged to hostility with that faithless city, and had assailed Saguntum for the purpose of bringing it about. On learning that war was declared, he immediately prepared to invade Italy itself, leading his army across the great mountain barrier of the Alps. He had already sent messengers to the Gauls, to invite their aid. They were found to be friendly, and eager for his coming. They had little reason to love Rome. A significant dream strengthened Hannibal's purpose. In his vision he seemed to see the supreme god of his fathers, who called him into the presence of all the gods of Carthage, seated in council on their thrones. They solemnly bade him to invade Italy, and one of the council went with him into that land as guide. As they passed onward the divine guide warned, "See that you look not behind you." But at length, heedless of the command, the dreamer turned and looked back. He saw behind him a monstrous form, covered thickly with serpents, while as it moved houses, orchards, and woods fell crashing to the earth. "What mighty thing is this?" he asked in wonder. "You see the desolation of Italy," replied the heavenly guide; "go on your way, straight forward, and cast no look behind." And thus, at the age of twenty-seven, Hannibal, at the command of his country's gods, went forward to the accomplishment of his early vow. His route lay through northern Spain, where he conquered all before him. Then he marched through Gaul to the Rhone. This he crossed in the face of an army of hostile Gauls, who had gathered to oppose him. He had more difficulty with his elephants, of which he had thirty-seven. Rafts were built to convey these great beasts across the stream, but some of them, frightened, leaped overboard and drowned their drivers. They then swam across themselves, and all were safely landed. [Illustration: HANNIBAL CROSSING THE ALPS.] Other difficulties arose, but all were overcome, and at length the mountains were reached. Here Hannibal was to perform the most famous of his exploits, the crossing of the great chain of the Alps with an army, an exploit more remarkable than that which brought similar fame to Napoleon in our own days, for with Hannibal it was pioneer work, while Napoleon profited by his example. The mountaineers proved to be hostile, and gathered at all points that commanded the narrow pass. But they left their posts at night, and Hannibal, when nightfall came, set out with a body of light troops and occupied all these posts. When morning dawned the natives, to their dismay, found that they had been outgeneralled.