Battle of the Allia

At the River Allia, north of Rome, a Roman force attempted to block a Gallic army advancing into central Italy. The Roman line collapsed, and survivors fled toward Veii or Rome.

The defeat was followed by the Gallic occupation and sack of much of the city. Later Roman memory treated the date as a day of disaster and used the episode to explain enduring fear of northern invaders.

The event is one of the earliest defeats examined in Ian Hughes’s Thirteen Roman Defeats and illustrates the uncertain evidence for Rome’s early military organisation.