Camillus's triumph over Veii was followed almost immediately by disgrace: accused of taking more than his share of the captured city's wealth, and resented for a vow that diverted a tenth of the spoils to Apollo at Delphi rather than to the soldiers who had won them, he was condemned and went into exile at Ardea. Roman tradition treats what happened next as poetic justice for the city that had rejected him. In 390 BCE a Gallic army under Brennus defeated Rome's forces at the Allia and sacked the city itself, holding it, apart from a besieged garrison on the Capitoline Hill, for months.
With Rome in ruins and its people ready by some accounts to abandon the site altogether and resettle at Veii, the Senate recalled Camillus, who is credited with rallying what remained of Roman military strength, driving the Gauls out, and, more consequentially for how Romans remembered him, arguing successfully against relocation and for rebuilding the city where it stood. That intervention earned him the title later writers gave him, the second founder of Rome, a designation resting less on any single battle than on the claim that Roman continuity itself, the decision to remain Rome rather than become something else, ran through him. He went on to hold the dictatorship five times in total, and later Roman tradition credited him with helping resolve the long running Struggle of the Orders between patricians and plebeians, dedicating a temple to Concord to mark the settlement.