Brennus (or Brennos) (died 279 BC at Delphi, Ancient Greece) was one of the Gaulish leaders of the army of the Gallic invasion of the Balkans. While invading the Greek mainland he managed to momentarily reach as far south as Delphi in an attempt to loot the rich treasury of the sanctuary of Apollo. His army suffered a devastating defeat at Delphi; he was heavily injured during the battle and committed suicide there. His militarily inexperienced army was forced to a continuous retreat by the tactical attacks of the Greek city-states and was cut down to a remaining band that fled from Greece.