It was an easy matter to conquer the enemy in open battle, but to support his own army was more difficult, for all Italy had been devastated.

On the other hand, the Romans were well supplied with food from their possessions in Sicily.
Hannibal saw, therefore, that more active measures than those already employed were necessary.

He sent to Carthage an appeal for aid.

He formed an alliance with Philip V.of Macedonia, and earnestly urged Hasdrubal Baroa, his lieutenant in Spain, to come to his assistance.

He hoped, with this army from the north, with supplies and reinforcements from Carthage, and with such troops as he might obtain from Macedonia, to concentrate a large force at Rome and compel her into submission.
The Romans, realizing the position of Hannibal, kept what forces they could spare in Spain, under the two Scipio brothers, Publius and Gnaeus.
With these they hoped to stop reinforcements from reaching the enemy from that quarter.