Brennus (4th century BC)

Brennus (or Brennos) was a chieftain of the Senones. He defeated the Romans at the Battle of the Allia (18 July 390 BC). In 387 BC he led an army of Cisalpine Gauls in their attack on Rome and captured most of the city, holding it for several months. Brennus's sack of Rome was the only time the city was occupied by a non-Roman army before the fall of the city to the Goths in 410 AD.

The Senones were a Gaulish tribe originating from the modern areas of France known as Seine-et-Marne, Loiret, and Yonne, who had expanded to occupy northern Italy. About 400 B.C. a branch of the Senones made their way over the Alps and, having driven out the Umbrians, settled on the east coast of Italy from Ariminum to Ancona, in the so-called Ager Gallicus, and founded the town of Sena Gallica (Sinigaglia), which became their capital.

In 391 they invaded Etruria and besieged Clusium. The Clusines appealed to Rome. Quintus Fabius Ambustus and his two brothers were sent to negotiate with the Gauls. They allegedly broke their oath of neutrality by participating in hostilities outside of Clusium. Livy and Plutarch say that the Senones marched to Rome to exact retribution for this.

It is possible that the entire story of the events at Clusium is fiction, as Clusium had no real reason to appeal to Rome for help, and the Gauls needed no real provocation to sack Rome. The story, it is hypothesized, exists to provide an explanation for an otherwise unmotivated attack on Rome, and to depict Rome as a bulwark of Italy against the Gauls. Alternately it has been theorized that Brennus was working in concert with Dionysius of Syracuse, who sought to control all of Sicily. Rome had strong allegiances with Messana, a small city state in north east Sicily, which Dionysius wanted to control. Rome's army being pinned down by Brennus' efforts would assist Dionysius's campaign.

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