The Battle of Cannae is a major battle of the Second Punic War, which takes place on August 2, 216 BCE near the town of Cannae in Apulia in southeast Italy.

The army of Carthage under Hannibal decisively defeats a numerically superior army of the Roman Republic under command of the consuls Lucius Aemilius Paullus and Gaius Terentius Varro.

It is regarded as one of the greatest tactical feats in military history and, in terms of the numbers killed, the second greatest defeat of Rome (second to the Battle of Arausio).Having recovered from their previous losses at Trebia (218 BC) and Trasimene (217 BCE), the Romans decide to engage Hannibal at Cannae, with roughly 86,000 Roman and Allied troops.

The Romans mass their heavy infantry in a deeper formation than usual while Hannibal utilizes the double-envelopment tactic.

This is so successful that the Roman army is effectively destroyed as a fighting force.

Following the Battle of Cannae, Capua and several other Italian city-states defect from the Roman Republic to Carthage.