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2 August 216 BCEReputable source · 2 sourcesDebated

At Cannae, Hannibal Let His Center Collapse on Purpose, Then Closed the Trap From Both Sides

On the timeline · around 2 August 216 BCE · The RepublicThe RepublicAt Cannae, Hannibal Let His Center Collapse on Purpose, Then Closed the Trap From Both Sides325 BCE300 BCE275 BCE250 BCE225 BCE200 BCE175 BCE150 BCE125 BCE100 BCE

What happened

Following his crossing of the Alps and early victories in Italy, Hannibal met a much larger Roman army in Apulia. Hannibal placed weaker Gallic and Spanish infantry at his center, arranged in a forward-bulging crescent, with his more seasoned African infantry held back on the flanks and his cavalry on the wings. As the Roman legions pushed into the center, that weaker infantry fell back and the crescent inverted, drawing the Roman mass deeper in while the flanks held firm. Hannibal's cavalry then routed the outnumbered Roman cavalry on the wings and swept around behind the Roman formation, closing a ring around them from the rear while the African infantry pressed in from the sides. Packed too tightly to fight or retreat, the encircled Roman army was cut down over the following hours.

Why it matters

Cannae remains one of history's most cited examples of a double envelopment, a maneuver where both flanks and the rear of an enemy force are sealed off simultaneously, and it is still taught in military history courses today as a reference case for encirclement tactics. Ancient writers give Roman losses ranging as high as around 70,000 dead, but modern historians treat these figures with real caution, since ancient armies and casualties were prone to inflation, and some modern reassessments put the true Roman death toll closer to 30,000. Whatever the precise number, it stands as the single deadliest day for Roman arms in the Republic's history, and Hannibal remained undefeated in Italy for over a decade afterward.

How we know

The two full ancient narrative accounts are Polybius, writing within a lifetime of the battle, and Livy, writing about two centuries later, both describing the crescent formation and the flanking cavalry action, though they disagree sharply on the death toll. Modern historians, including those writing in academic classics resources, treat both ancient figures as likely inflated and have proposed considerably lower estimates based on comparison with Roman army size records elsewhere.

Sources

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Part of a timelineAncient Rome30 events · From a legendary fratricide on the Palatine Hill to a teenage emperor's quiet deposition twelve centuries later, told through the battles, plagues, and one bridge-crossing that ended a republic.View all →