Titus Livius (Livy), The History of Rome, Book 7
Benjamin Oliver Foster, Ph.D., Ed.

7. But before the dictator and his new levies were got to the country of the Hernici, the lieutenant Gaius Sulpicius, profiting by a favourable opportunity, had fought a brilliant engagement. [2] The Hernici, whom the consul's death had made contemptuous, approached the Roman camp with every expectation of taking it by storm; but the soldiers, heartened by their general and bursting with anger and resentment, made a sortie, and so far were the Hernici from attacking the stockade, as they had hoped to do, that they actually fell back in confusion from the ground. [3] Then came the dictator, and the new army was joined to the old and the forces doubled. Calling the men together, Appius lauded the lieutenant and his soldiers, by whose bravery the camp had been defended; thus at the same stroke he encouraged those who heard themselves deservedly commended, and stimulated the others to emulation of their conduct. [4] Nor were the enemy less energetic in making ready for the war; mindful of the glory they had won [p. 379]before, and aware that the forces of their adversaries¹ had been augmented, they also strengthened theirs. All who bore the name of Hernici and were of military age were called upon, and eight cohorts were formed, each numbering four hundred of their best men. [5] This choice flower of their manhood they inspired with additional hope and courage by a decree which allowed them double pay. They were exempted, also, from military tasks, in order that, being reserved for the one labour of fighting, they might be sensible of an obligation to exert themselves beyond the capacity of ordinary men. [6] Finally, they were assigned a post in the battle outside the line, to make their bravery the more conspicuous.

A plain extending for two miles separated the Roman camp from the Hernici. In the middle of this plain, at a spot almost equidistant from both camps, the battle was fought. [7] At first the event of the struggle was in doubt and nothing came of the oft-repeated attempts of the Roman horse to break the enemy's line. [8] Finding their charges ineffectual, despite their efforts, they consulted the dictator and with his permission left their horses, and, rushing to the front with a mighty cheer, inaugurated a new kind of fighting. [9] There would have been no stopping them, had it not been for the special cohorts, who flung themselves across their path with a vigour and gallantry equal to their own.