Siege of Capua (211 BC) shortly afterwards. Polybius - The Rise of the Roman Empire, pp 387–394 Siege of Capua (211 BC) The Siege of Capua was fought in 211 BC, when the Romans besieged Capua. It is described by Polybius at 9.4-7, and by Livy at 26.4-6. Capua had defected to Hannibal after the Battle of Cannae in 216 BC. Hannibal had made Capua his winter quarter in 215 BC and had conducted his campaigns against Nola and Casilinum from there. The Romans had attempted to march on Capua several times since its defection but were thwarted by the return of Hannibal's army rushing
Socii to raise a double-strength army of four legions and four "alae" e.g. at the Battle of Cannae in 216 BC, where each Consul commanded an army of about 40,000 men. Polybius states that the Romans and their allies could draw on a grand total of 770,000 men fit to bear arms (of which 70,000 met the property requirement for cavalry) in 225 BC, shortly before the start of the Second Punic War. The Romans reportedly asked their allies for an urgent register of all "men fit to bear arms" for a "tumultus Gallicus". Polybius' subtotals, however, are garbled, as he