The Capitoline Hill was the only part of the city of Rome that resisted the invasion of the Gauls from the Po valley in 390 BCE. The Gauls decided to conquer the hill at night.
For this purpose, they chose the steepest approach and the moment when the defenders, tired of prolonged fights and hunger, fell asleep. The geese, birds dedicated to the goddess Juno, had warned them of the enemy’s approach. The attack was repulsed.
The defenders not only defended the hill but drove the enemy out of Rome. In memory of this event, the ancient Romans carried one of the geese in a litter. Dogs that fell asleep with humans were punished (one of them was hanged).