Why did Hannibal’s centre line fall back during the Battle of Cannae?

At the Battle of Cannae, Hannibal’s centre line—composed of Gallic and Spanish infantry—fell back as a deliberate tactical maneuver rather than a sign of defeat.12

Hannibal intentionally positioned his troops in a crescent formation, with the centre advanced and his elite African infantry stationed on the flanks. When the numerically superior Roman infantry attacked, they were able to push the Carthaginian centre backward. However, because the centre held its formation without breaking, this retreat served to draw the Roman forces deeper into a trap.12

As the Romans advanced, they were gradually surrounded by the African troops on the flanks and the returning Carthaginian cavalry, resulting in a classic double envelopment that led to the destruction of the Roman army.12