The Battle of the Allia was one of the monumental defeats in Roman history. Tradition has it that Brennus and his band of warriors were migrating Senones Gauls who went considerably further south into the Italic peninsula than the other Gallic tribes, the Insubres, who had arrived in about 600 B.C., followed by the Cenomani, Libui, Salui, Boii, and Lingones. However, it is likely that Brennus and company were a mercenary band who later hired on to help the tyrant Dionysius of Syracuse.
Sides in the Battle of the Allia:
The Celts (or Gauls) outnumbered and fought against the Romans. There were probably about 30,000 Celts to 10-15,000 Romans or 70,000 to 40,000.
Date of the Battle of the Allia:
On July 18 c. 390 or c. 387 B.C.
Winners and Losers:
- Winners - Gauls (Brennus).
- Losers - Romans (Q.Servius Fidenas, Q.Sulpicius, P.Cornelius Maluginensis).
The Allia was a tributary of the Tiber River north of Fidenae.
Outcome of the Battle of the Allia:
The Romans were badly defeated, although we don't know how many escaped by swimming across the Tiber and fleeing to Veii. The defeat at Allia ranked with Cannae as the worst disasters in Roman Republican military history.
After a brief delay the Celts went on to Rome, which they sacked and occupied -- all except the Capitol, which remained safe partly because, according to popular legends, geese alerted the defenders to the presence of enemy Celts. After months of siege, the Celts were bribed with gold and left. Another story is that as the Romans weighed out the gold payment, and grumbled about it, Brennus threw his sword on the weights side, adding to the amount of gold the Romans needed to surrender and said, "Vae victis" [Woe to the conquered].
- The loss by the Romans made their neighbors somewhat less respectful. The Aequi, Volsci and Etruscans re-opened hostilities.
- The Romans built a a solid stone wall 12' thick and 24' high around the 5-1/2 miles of their city. This is the Servian Wall.
- The Romans realized that they had been defeated by Gallic swordsmen and so their battle tactics had to be revised.
Some Ancient Sources: