Hannibal felt all the importance of deciding the wavering sentiments of this people; on them his future success or defeat depended; to do this nothing but victory was requisite. He accordingly advanced rapidly against the Romans, and first engaged them in a cavalry action at the Ticinus. Victory declared for the Carthaginians. The horse of Numidia routed the cavalry of Rome. This success, unimportant as it was, revealed Hannibal to the eyes of the Gauls; influenced by it, the Insubrian chiefs hastened to supply him with provisions and troops. Hardly had the Carthaginians arrived in sight of the Roman camp at Placentia, when a large body of the Gaulish contingent revolted from Scipio, and contrived, though much reduced in numbers, to cut their way through in spite of all opposition, and join Hannibal. The famous battle of the Trebia--the first of those great victories which have rendered immortal the genius of the Carthaginian chief--soon followed; it at once decided the course of Cisalpine Gaul. Its immediate and ultimate effects on the power and operations of Hannibal are well developed by our author:-- "The fortune of Hannibal was then consolidated; more than 60,000 Boians, Insubrians, and Ligures flocked in a few days to his standards, and raised his forces to 100,000 men. With such a disproportion between the nucleus of the Carthaginian army and its auxiliaries, Hannibal was in reality but a Gaulish chief; and if, in the moments of danger, he had no cause to repent his new situation, more than once, nevertheless, he cursed with bitterness its inconveniences. Nothing could equal the courage and devotion of the Gaulish soldier in the dangers of the battle-field; but under the tent he had neither the habit nor the taste of military subordination. The lofty conceptions of Hannibal surpassed his comprehension; he could not understand war, unless such as he himself carried it on--as a bold and rapid plundering excursion, of which the present moment reaped the whole advantage. He would have wished to march instantly on Rome, or at least to pass the winter in some of the allied or subject provinces--in Etruria or in Umbria--there to live at discretion in pillage and license. Did Hannibal represent that it was necessary to spare the provinces in order to gain them over to the common cause, the Cisalpines broke forth into murmurs; the combinations of prudence and genius appeared in their eyes but a vile pretext to deprive them of the advantages which they had legitimately won."--(I. 292-293.)