The battle was a disaster because the shear volume of men in the Gallic force was more than the defenders could handle and the Roman position was easily flanked. Half of the army was killed and the survivors retreated to Veii, on the other side of the Tiber.
Now the city was defenseless and open to plunder. The Vestal Virgins and priests gathered up the sacred relics and fled to Caere, while the remnants of the senate and army retreated to the top of the Capitoline Hill, prepared to resist any Gallic attempt to storm the citadel. The Gauls entered the city, plundered it, and set it on fire. They seemed content to let those on the Capitoline starve, and only tried to attack it on a couple of occasions. For seven months they occupied the city.