Brennus (or Brennos) was a leader of the Senones, a Gallic tribe. Around 387 BC, he defeated the Romans in the Battle of the Allia. Later that same year, he led an army of Cisalpine Gauls in an attack on Rome. His forces captured most of the city and held it for several months. Brennus's capture of Rome was the only time in 800 years that the city was occupied by a non-Roman army. This event occurred before Rome was later captured by the Germanic Visigoths in 410 AD.
Background
The Senones were a group of people from ancient Gaul, which is now part of France, including areas such as Seine-et-Marne, Loiret, and Yonne. Around 400 BC, some Senones traveled over the Alps and moved to northern Italy. They drove out the Umbri and settled along the east coast of Italy, from Ariminum to Ancona, in a region called Ager Gallicus. They built a city named Sena Gallica, which is now known as Senigallia, and made it their capital.
In 391 BC, the Senones attacked Etruria and surrounded the city of Clusium. The people of Clusium asked Rome for help. Three Roman leaders, including Quintus Fabius Ambustus and his brothers, were sent to speak with the Senones. They were accused of breaking their promise to stay neutral by fighting outside Clusium. According to the ancient writers Livy and Plutarch, the Senones then marched toward Rome to take revenge. Some historians believe the story of the events at Clusium may not be true, as Clusium had no clear reason to ask Rome for help, and the Senones may not have needed a reason to attack Rome. This story might have been created to explain why Rome was attacked and to show Rome as a protector of Italy. Another idea is that the Senones, led by Brennus, were working with Dionysius I of Syracuse, who wanted to control all of Sicily. Rome had strong friendships with Messana, a small city in Sicily that Dionysius wanted to control. If Rome’s army was busy fighting the Senones, it might have helped Dionysius’s plans.
Sack of Rome
During the Battle of the Allia, Brennus led the Senones to victory over the Romans and marched into the city. The Senones took control of Rome except for the Capitoline Hill, which the Romans successfully defended. According to legend, Marcus Manlius Capitolinus was warned about the Gallic attack by the sacred geese of Juno. Seeing their city destroyed, the Romans tried to buy their freedom from Brennus. The Romans agreed to pay 1,000 pounds of gold. According to Livy, during an argument about the scales used to weigh the gold (the Gauls had brought heavier-than-standard weights), Brennus placed his sword on the scales and said the famous words "Vae victis!", which means "woe to the conquered!"
Defeat
One version of the story says that the argument about the weights caused such a delay that the exiled leader Marcus Furius Camillus had more time to gather an army, return to Rome, and drive the Gauls away. This action saved the city and its treasury. Camillus told Brennus, "Not by gold, but by iron, is the nation to be recovered." According to Plutarch, after fighting through Rome's streets, the Gauls were first forced out of the city. They were then completely defeated in a battle eight miles outside the city on the road to Gabii. Camillus was honored by his soldiers as another Romulus, called "father of his country" or "Pater Patriae," and seen as the second founder of Rome.
Livy wrote that the Senones who were attacking the Capitoline Hill became sick with an illness and were weak when they had to leave. This is plausible because diseases like dysentery and problems with poor hygiene have made soldiers sick or caused their deaths throughout history, including in modern times.
Silius Italicus claimed that Hannibal's Boii cavalry were led by a man named Crixus, who was a descendant of Brennus. Crixus died during the Battle of Ticinus.