390 BC
July 18 – Battle of the Allia: Brennus, a chieftain of the Senones of the Adriatic coast of Italy, leads an army of Cisalpine Gauls in their attack on Rome. They capture the entire city of Rome except for the Capitoline Hill, which is successfully held against them. However, seeing their city devastated, the Romans attempt to buy their salvation from Brennus. The Romans agree to pay one thousand pounds weight of gold.