ian general effected his passage across the
river, notwithstanding the opposition of the Gauls; and when Scipio
marched up the left bank of the river he found that Hannibal had
advanced into the interior of Gaul, and was already three days in
advance of him. Despairing, therefore, of overtaking Hannibal, he
determined to sail back to Italy and await him in Cisalpine Gaul; but as
the Republic had already an army in that province, he sent the greater
part of his own forces into Spain under the command of his brother Cn.
Scipio. This prudent step probably saved Rome; for if the Carthaginians
had maintained the undisputed mastery of Spain, they might have
concentrated all their efforts to support Hannibal in Italy, and have
sent him such strong re-enforcements after the battle of Cannae as would
have compelled Rome to submit.

Hannibal, after crossing the Rhone, continued his march up the left bank
of the river as far as its confluence with the Isere. Here he interposed
in a dispute between two rival chiefs of the Allobroges, and, by lending
his aid to establish one of them firmly on the throne, secured the
co-operation of an efficient ally, who greatly facilitated his farther
progress. But in his passage across the Alps he was attacked by the
barbarians, and as he struggled through the narrow and dangerous defiles
the enemy destroyed numbers of his men. It was some days before he
reached the summit of the pass. Thenceforth he suffered but little from
hostile attacks, but the descent was difficult and dangerous. The
natural difficulties of the road, enhanced by the lateness of the season
(the beginning of October, at which time the snows had already commenced
in the high Alps), caused him almost as much loss as the opposition of
the barbarians on the other side of the mountains. So heavy were his
losses from these combined causes, that, when he at length emerged from
the valley of Aosta into the plains of the Po and encamped in the
friendly country of the Insubres, he had with him no more than 20,000
foot and 6000 horse.[31] Such were the forces with which he descended
into Italy to attempt the overthrow of a power that a few years before
was able to muster a disposable force of above 700,000 fighting men.

Five months had been employed in the march from New Carthage to the
plains of Italy, of which the actual passage of the Alps had occupied
fifteen days. Hannibal's first care was now to recruit the strength of
his troops