As the spring advanced the great magazines which Hannibal had brought with him became nearly exhausted, and no provisions could be obtained from the surrounding country, which had been completely ruined by the long presence of the two armies.  It became, therefore, necessary to move from the position which he had occupied during the winter.  The Romans possessed the great advantage over him of having magazines in their rear constantly replenished by their allies, and move where they might, they were sure of obtaining subsistence without difficulty.  Thus, upon the march, they were unembarrassed by the necessity of taking a great baggage train with them, and, when halted, their general could keep his army together in readiness to strike a blow whenever an opportunity offered; while Hannibal, on the other hand, was forced to scatter a considerable portion of the army in search of provisions.

The annual elections at Rome had just taken place, and Terentius Varro and Emilius Paulus had been chosen consuls.  Emilius belonged to the aristocratic party, and had given proof of military ability three years before when he had commanded as consul in the Illyrian war.  Varro belonged to the popular party, and is described by the historians of the period as a coarse and brutal demagogue, the son of a butcher, and having himself been a butcher.  But he was unquestionably an able man, and possessed some great qualities.  The praetor Marcellus, who had slain a Gaulish king with his own hand in the last Gaulish war, was at Ostia with a legion.  He was destined to command the fleet and to guard the southern coasts of Italy, while another praetor, Lucius Postumius, with one legion, was in Cisalpine Gaul keeping down the tribes friendly to Carthage.

But before the new consuls arrived to take the command of the army Hannibal had moved from Geronium.

The great Roman magazine of Apulia was at Cannae, a town near the river Aulidus.  This important place was but fifty miles by the shortest route across the plain from Geronium; but the Romans were unable to follow directly across the plain, for at this time the Carthaginians greatly outnumbered them in cavalry, and they would, therefore, have to take the road round the foot of the mountains, which was nearly seventy miles long; and yet, by some unaccountable blunder, they neglected to place a sufficient guard over their great magazines at Cannae to defend them for even a few days against a sudden attack.

Hannibal saw the opportunity, and when spring was passing into summer broke up his camp and marched straight to Cannae, where the vast magazines of the Romans at once fell into his hands.  He thus not only obtained possession of his enemy’s supplies, but interposed between the Romans and the low lying district of Southern Apulia, where alone, at, this early season of the year, the corn was fully ripe.