The Battle of the Allia was a battle fought between the Senones – a Gallic tribe led by Brennus, who had invaded Northern Italy – and the Roman Republic. The battle was fought at the confluence of the Tiber and Allia rivers, 11 Roman miles (16 km, 10 mi) north of Rome. The Romans were routed and subsequently Rome was sacked by the Senones. According to scholar Piero Treves, "the absence of any archaeological evidence for a destruction-level of this date suggests that [this] sack of Rome was superficial only." The date of the battle has been traditionally given as 390 BC in the Varronian chronology, based on an account of the battle by the Roman historian Livy. Plutarch noted that the battle took place "just after the summer solstice when the moon was near the full [...] a little more than three hundred and sixty years from the founding [of Rome]," or shortly after 393 BC. The Greek historian Polybius used a Greek dating system to derive the year as having taken place in 387 BC, which is the most probable. Tacitus listed the date as 18 July. Background The Senones were one of the various Gallic tribes that had recently invaded northern Italy. They settled on the Adriatic Coast around what is now Rimini. According to Livy, they were called to the Etruscan town of Clusium (now Chiusi, Tuscany) by Aruns, an influential young man of the city who wanted to take revenge against Lucumo, whose son had "debauched his wife." When the Senones appeared, the Clusians felt threatened and asked Rome for help. The Romans sent the three sons of Marcus Fabius Ambustus, one of Rome's most powerful aristocrats, as ambassadors. They told the Gauls not to attack Clusium and that if they did, the Romans would fight to defend the town. They then asked to negotiate peace. The Senones accepted peace if the Clusians would give them some land. There was a quarrel and a battle broke out. The Roman ambassadors joined in. One of them killed a Senone chieftain. That was a violation of the rule that ambassadors had to be neutral. The brothers had taken sides and one of them had also killed a Senone. The Gauls withdrew to discuss what action to take. According to Dionysius of Halicarnassus, Lucumo was the king of the city. He assigned the guardianship of his son to