"Punic Wars - Battle of Cannae in 216 B.C. - Battle of the Second Punic War"

Definition: During the Second Punic War, the Cathraginian leader Hannibal's greatest victory occurred at Cannae. There, with a substantially smaller force, Hannibal encircled the Roman troops and used his cavalry to crush the Roman infantry. He hamstrung those who fled so he could later return to finish the job. Of 70,000 Roman troops at Cannae, less than 2000 survived. In two years, Hannibal had defeated the equivalent of 8 consular armies. After Cannae, Capua and other smaller Italian cities defected to Hannibal's side.

See Polybius on the Battle of Cannae