The first of the three greatest defeats the Romans suffered was at the Allia, a stream near Rome, in about 390 B.C., on July 18. In this battle Brennus led the Gauls in a rout against a roughly evenly matched group of Romans under Quintus Sulpicius. The Romans needed to re-evaluate their battle tactics. As a result of the defeat, the Gauls could march on Rome. The Roman leader Camillus had to be recalled as dictator of the Romans to get rid of the invading Gauls.
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