Gallic Sack of Rome (390 BC) and the Battle of the Allia

The Gallic sack of Rome, traditionally dated to 390 BC, was the only time in nearly 800 years that a foreign army captured the city. Celtic Gauls of the Senones tribe, led by a chieftain the Romans called Brennus, routed the Roman army at the Battle of the Allia and occupied Rome, while defenders held out on the Capitoline Hill. The Gauls left after receiving a ransom in gold, but the disaster left a deep and lasting mark on Roman memory.

Background: the Gauls in Italy

From around the 5th century BC, Celtic peoples from beyond the Alps, whom the Romans called Galli, settled in the Po valley of northern Italy, displacing or mixing with Etruscans and others. The Senones settled furthest south-east, along the Adriatic coast in what is now the Marche region.

Rome at this time was a growing power in central Italy. It had just captured its Etruscan rival in the fall of Veii in 396 BC, but it had little experience of warfare against the Gauls, who fought with long swords and terrifying charges.

The incident at Clusium

According to Livy, the Senones crossed the Apennines and besieged the Etruscan city of Clusium (modern Chiusi), which asked Rome for help. Rome sent three envoys, sons of Marcus Fabius Ambustus, to negotiate. Instead of remaining neutral, the envoys joined the fighting, and Quintus Fabius killed a Gallic chieftain.

The Gauls regarded this as a breach of the law of nations, which protected envoys only so long as they did not take part in battle. They demanded that Rome hand over the Fabii. The Roman people refused and instead elected the three brothers military tribunes, magistrates with consular power, for the following year. The Gauls marched on Rome.

The Battle of the Allia

The two armies met on 18 July, according to Roman tradition, near the junction of the small river Allia with the Tiber, about 11 Roman miles (some 16 km) north of Rome. The Romans may have been outflanked as they tried to extend their line to match the Gallic numbers. The army broke in panic; many soldiers drowned trying to cross the Tiber, and many survivors fled to the abandoned city of Veii rather than back to Rome.

Ancient figures for the size of the armies are unreliable. Later Romans marked 18 July as the dies Alliensis, the “day of the Allia”, an unlucky date on which no public business was done.

Rome occupied

With the army scattered, Rome was almost defenceless. According to Livy, men of fighting age, the Senate and as many supplies as possible were taken up to the Capitol, the fortified hilltop citadel. The Vestal Virgins carried the sacred objects to the friendly Etruscan city of Caere, helped by a plebeian named Lucius Albinius, who gave them his cart.

Livy says elderly former magistrates remained in their homes, seated in their robes of office. When a Gaul stroked the beard of one of them, Marcus Papirius, the old man struck him with his ivory staff, and the massacre began. The city was then plundered and burned.

The Gauls besieged the Capitol for months; Polybius says they held the city for seven months. One night they climbed the cliff unseen, but the sacred geese of Juno cackled and woke the former consul Marcus Manlius, who pushed the first attacker off the rock and rallied the defenders. He was honoured with the name Capitolinus.

The ransom and “Vae victis”

Hunger and disease affected both sides, and the Romans agreed to pay the Gauls to leave. The price, according to Livy, was 1,000 pounds of gold. When the Romans protested that the Gauls’ weights were false, Brennus threw his sword onto the scales and said “Vae victis”, “Woe to the vanquished.”

Livy goes on to tell how Camillus, recalled from exile and named dictator, arrived at that moment, declared the bargain void and defeated the Gauls. Most historians regard this as a patriotic invention. Polybius says the Gauls left with the gold because the Veneti were attacking their homeland, and other traditions say the gold was recovered later.

Myths and facts

Myth: Camillus saved the gold and destroyed the Gauls. This is Livy’s version, but it appears to have been added to soften a humiliating defeat. Polybius, writing earlier, records no such rescue, and the Gauls seem to have left with their payment.

Myth: the Gauls burned all of Rome to the ground. Roman writers believed the city was almost wholly destroyed. Excavations have not confirmed a city-wide fire of this date; a burnt layer in the Comitium once linked to the sack belongs to an earlier period.

Fact: the geese were remembered in ritual. Whatever the truth of the night attack, Romans later held an annual procession in which a goose was carried in honour and dogs, which had failed to bark, were punished. The story was part of Roman religious life for centuries.

Fact: the date is uncertain. The Roman date of 390 BC comes from Varro’s chronology, which is now known to run several years too early for this period. Greek synchronisms place the sack in 387/386 BC, the year of the King’s Peace in Greece.

Key people

• Brennus: leader of the Senones, otherwise unknown; his name may be a title.
• Marcus Manlius Capitolinus: defender of the Capitol; later accused of aiming at tyranny and executed, traditionally in 384 BC.
• Marcus Furius Camillus: conqueror of Veii, celebrated by Livy as the saviour and “second founder” of Rome.
• The Fabii: the envoys whose actions at Clusium provoked the war.

Consequences

Rome recovered quickly. Livy claims the city was rebuilt so hastily that its streets became irregular. Proposals to move the population to Veii were rejected. Rome soon built a massive new defensive circuit, now called the Servian Wall, begun around 378 BC with stone from quarries in former Veientine territory.

Historians also believe the destruction of records in the sack helps explain why Rome’s earlier history is so poorly documented, although some records evidently survived. Archaeologists have not found a clear destruction layer, suggesting the damage was less complete than Roman writers believed.

Fear of the Gauls, the metus Gallicus, shaped Roman policy for centuries. Further Gallic raids followed in the 4th century, and Rome defeated a Gallic and Samnite coalition at the Battle of Sentinum in 295 BC. Julius Caesar’s Gallic Wars of 58–50 BC were presented partly as removing this ancient threat. The city was not taken again by a foreign enemy until the sack of Rome in 410 by Alaric’s Visigoths.

Timeline

• c. 400 BC: The Senones settle on the Adriatic coast of Italy.
• 396 BC: Rome captures Veii.
• 390 BC (or 387/386 BC): The Gauls besiege Clusium; Roman envoys join the fighting.
• 390 BC, 18 July: The Romans are routed at the Battle of the Allia.
• 390 BC: Rome is sacked; the Capitol holds out; the geese warn Manlius of a night attack.
• 390 BC: The Gauls leave after receiving a ransom in gold.
• c. 378 BC: Construction of the Servian Wall begins.
• 295 BC: Rome defeats Gauls and Samnites at Sentinum.

Why it matters

The Gallic sack was Rome’s greatest early humiliation and a defining memory of vulnerability. It pushed Rome to build stronger walls and reorganise its army, and the lessons Romans drew from it helped drive the expansion that followed.