All through the winter and spring the two armies remained encamped opposite each other, and it was not until the season was advanced enough for them to get supplies from the year's crops that Hannibal moved his forces out of the camp near Geronium.
Judging that it was in his interest to compel the enemy to fight by every means in his power, he seized on the citadel of a town called <a class="linkToPlace" target="_blank" href="/place?placename=Cannae&groupId=430&placeId=797">Cannae</a>,
in which the Romans had collected the corn and other supplies from the country round Canusium, conveying hence to their camp from time to time enough to supply their wants.
The city itself had previously been razed, but the capture now of the citadel and stores caused no little commotion in the Roman army; for they were distressed at the fall of the place
not only owing to the loss of their supplies, but because it commanded the surrounding district.
They continued, therefore, to send constant messages to <a class="linkToPlace" target="_blank" href="/place?placename=Rome&groupId=935&placeId=1669">Rome</a> asking how they should act, stating that if they approached the enemy they would not be able to escape a battle, as the country was being pillaged and the temper of all the allies was uncertain.
The Senate decided to give the enemy battle, but they ordered Servilius to wait, and dispatched the Consuls to the front.
It was to Aemilius that the eyes of all were directed; and they placed their chiefest hope in him, owing to his general high character, and because a few years previously he was thought to have conducted the Illyrian war with courage and advantage to the state.
They decided to bring eight legions into the field, a thing which had never been done before by the Romans, each legion consisting of about five thousand men apart from the allies.
For, as I previously explained, they invariably employ four legions, each numbering about four thousand foot and two hundred horse,
but on occasions of exceptional gravity they raise the number of foot in each legion to five thousand and that of the cavalry to three hundred.
They make the number of the allied infantry equal to that of the Roman legions, but, as a rule, the allied cavalry are three times as numerous as the Roman.
They give each of the Consuls half of the allies and two legions when they dispatch them to the field,
and most of their wars are decided by one Consul with two legions and the above number of allies, it being only on rare occasions that they employ all their forces at one time and in one battle.
But now they were so alarmed and anxious as to the future that they decided to bring into action not four legions but eight.
Walbank Commentary