18 Julho

In 387 or 386 BCE (or 390 according to the Varronian chronology), an army of Gallic mercenaries that was allied to the ruler of Syracuse, Dionysius, marched through the valley of the Tiber. The Romans tried to repel them at a brook called Allia, but they were not accustomed to the "shock and awe" way of fighting of the Gauls. Almost immediately after the two armies had made contact, the Roman commanders ordered the retreat. Since Rome was too big to have a city wall, the soldiers went to nearby Veii. As a result, Rome was occupied by the Gauls, who tried to capture the Capitol. After seven months, the Roman garrison bought its freedom for 1000 pounds of gold.

The battle was less disastrous than later Roman historians (e.g., Livy) assumed, but nevertheless, the "day of the Allia" (18 July) was considered to be an unlucky one for centuries to come.

Thus picture shows the southern part of the battlefield, seen from the east. The Tiber is in the background.