In 211 BC, during the Second Punic War, Hannibal Barca launched a bold attack on Rome, in the famous episode known as "Hannibal ad portas". The main sources, Livy and Polybius, describe this event as a strategic move to divert the Romans from the siege of Capua, an ally of Carthage. 

After devastating Campania, Hannibal advanced rapidly toward Rome with his army. According to Livy, panic spread among the Roman citizens. However, Rome was well-prepared: its walls were fortified and the consuls had deployed a massive army. Polybius emphasizes that Hannibal, because of the luck of war machines and reinforcements, knew that a true siege was impossible. 

After ravaging the countryside around Rome and camping his Carthaginian army just three miles from the city walls, Hannibal attempted to provoke an open-field battle, but the Romans refused to engage. Realizing that capturing Rome was impossible, Hannibal withdrew to Bruttium, where he continued to fight. Though his attempt failed militarily, it strengthened his legend, inspiring both fear and admiration among the Romans.