Defence in depth in order to retreat successfully, and they assume that the defender's morale will recover from the retreat. A possible early example of this came at the Battle of Cannae in 216 BC, when Hannibal employed this manoeuvre in order to encircle and destroy eight Roman legions, but that is disputed by some historians. Edward Luttwak used the term to describe his theory of the defensive strategy employed by the Late Roman army in the 3rd and 4th centuries AD. Later examples of defence in depth might be European hill forts and the development of concentric castles. In those examples, the
Carthago delenda est seafaring Phoenician city-state of Carthage in North Africa (modern day Tunisia), they suffered a number of humiliations and damaging reverses in the course of these engagements, especially at the Battle of Cannae (216 BC). This grew into an attitude of seeking vengeance and total victory, which was expressed by these phrases. The city of Carthage was indeed finally razed by the Roman general Scipio Aemilianus after the Third Battle of Carthage in 146 BC, and its entire remaining population was sold into slavery. It thus never again posed a threat to Rome—at least until taken over by the Vandals, who