In 212 BC conspirators in Tarentum let Hannibal into the city. They then blew the alarm with some Roman trumpets. This let Hannibal's troops pick off the Romans as they stumbled into the streets. Hannibal told the Tarentines to mark every house where Tarentines lived so they wouldn't be looted. Even with the looting the citadel held out. This stopped Hannibal from using the harbor and Rome was slowly gaining ground over Hannibal. In the same year, he lost Campania.