Plutarch, Marcellus
Bernadotte Perrin, Ed.

7. Meanwhile the king of the Gauls espied him, and judging from his insignia that he was the commander, rode far out in front of the rest and confronted him, shouting challenges and brandishing his spear. His stature exceeded that of the other Gauls, and he was conspicuous for a suit of armour which was set off with gold and silver and bright colours and all sorts of broideries; it gleamed like lightning. [2] Accordingly, as Marcellus surveyed the ranks of the enemy, this seemed to him to be the most beautiful armour, and he concluded that it was this which he had vowed to the god. He therefore rushed upon the man, and by a thrust of his spear which pierced his adversary's breastplate, and by the impact of his horse in full career, threw him, still living, upon the ground, where, with a second and third blow, he promptly killed him. [3] Then leaping from his horse and laying his hands upon the armour of the dead, he looked towards heaven and said: ‘O Jupiter Feretrius, who beholds the great deeds and exploits of generals and commanders in wars and fightings, I call thee to witness that I have overpowered and slain this man with my own hand, being the third Roman ruler and general so to slay a ruler and king, and that I dedicate to thee the first and most beautiful of the spoils. Do thou therefore grant us a like fortune as we prosecute the rest of the war.’

[4] His prayer ended, the cavalry joined battle, fighting, not with the enemy's horsemen alone, but also with their footmen who attacked them at the same time, and won a victory which, in its sort and kind, was remarkable and strange. For never before or since, as we are told, have so few horsemen conquered so many horsemen and footmen together. After slaying the greater part of the enemy and getting possession of their arms and baggage, Marcellus returned to his colleague, who was hard put to it in his war with the Gauls near their largest and most populous city.¹ [5] Mediolanum was the city's name, and the Gauls considered it their metropolis; wherefore they fought eagerly in its defence, so that Cornelius was less besieger than besieged. But when Marcellus came up, and when the Gaesatae, on learning of the defeat and death of their king, withdrew, Mediolanum was taken, the Gauls themselves surrendered the rest of their cities at the disposition of the Romans. They obtained peace on equitable terms.