Utilizing its doctrine of frontal assault in waves, Varro's army found itself surrounded as the enemy line's convex formation collapsed into a concave line, and the Numidians under Marharbal rode around the Roman flanks to complete the encirclement.  
The Roman army was under command of Consul Varro, who would survive the slaughter awaiting his troops despite being struck in the head with a slinger stone.  Utilizing its doctrine of frontal assault in waves, Varro's army found itself surrounded as the enemy line's convex formation collapsed into a concave line, and the Numidians under Marharbal rode around the Roman flanks to complete the encirclement.  For ten points, name this 216 BC battle, the most famous victory of the Carthaginian general Hannibal.
The Roman army was under command of Consul Varro, who would survive the slaughter awaiting his troops despite being struck in the head with a slinger stone.  
{Cannae}