The History of Rome (1.12.1-1.12.5)

However this may be, the Sabines were in possession of the citadel. And they would not come down from it the next day, though the Roman army was drawn up in battle array over the whole of the ground between the Palatine and the Capitoline hill, until, exasperated at the loss of their citadel and determined to recover it, the Romans mounted to the attack.

Advancing before the rest, Mettius Curtius, on the side of the Sabines, and Hostius Hostilius, on the side of the Romans, engaged in single combat.

Hostius, fighting on disadvantageous ground, upheld the fortunes of Rome by his intrepid bravery, but at last he fell; the Roman line broke and fled to what was then the gate of the Palatine.

Even Romulus was being swept away by the crowd of fugitives, and lifting up his hands to heaven he exclaimed: “ Jupiter, it was thy omen that I obeyed when I laid here on the Palatine the earliest foundations of the City. Now the Sabines hold its citadel, having bought it by a bribe, and coming thence have seized the valley and are pressing hitherwards in battle.

Do thou, Father of gods and men, drive hence our foes, banish terror from Roman hearts, and stay our shameful flight!