Pompey himself led the right wing of his army against Antony, and placed his father-in-law, Scipio, in the middle against Lucius Calvinus. The left wing was commanded by Lucius Domitius, and supported by the great mass of the horse. For almost the whole cavalry was posted there in the hope of crushing Caesar, and cutting off the tenth legion, which was spoken of as the stoutest in all the army, and in which Caesar himself usually fought in person. Caesar observing the left wing of the enemy to be lined and fortified with such a mighty guard of horse, and alarmed at the gallantry of their appearance, sent for a detachment of six cohorts out of the reserves, and placed them in the rear of the tenth legion, commanding them not to stir, lest they should be discovered by the enemy; but when the enemy's horse should begin to charge, and press upon them, that they should make up with all speed to the front through the foremost ranks and not throw their javelins at a distance, as is usual with brave soldiers, that they come to a close fight with their swords the sooner, but that they should strike them upwards into the eyes and faces of the enemy; telling them that those fine young dancers would never endure the steel shining in their eyes, but would fly to save their handsome faces. This was Caesar's employment at that time. But while he was thus instructing his soldiers, Pompey on horseback was viewing the order of both armies, and when he saw how well the enemy kept their ranks, expecting quietly the signal of battle, and, on the contrary, how impatient and unsteady his own men were, waving up and down in disorder for want of experience, he was very much afraid that their ranks would be broken upon the first onset; and therefore he gave out orders that the van should make a stand, and keeping close in their ranks should receive the enemy's charge. Caesar much condemns this command; which, he says, not only took off from the strength of the blows, which would otherwise have been made with a spring, but also lost the men the impetus, which, more than anything, in the moment of their coming upon the enemy, fills soldiers with impulse and inspiration, the very shouts and rapid pace adding to their fury; of which Pompey deprived his men, arresting them in their course and cooling down their heat.
Caesar's army consisted of twenty-two thousand, and Pompey's of somewhat above twice as many. When the signal of battle was given on both sides, and the trumpets began to sound a charge, most men of course were fully occupied with their own matters; only some few of the noblest Romans, together with certain Greeks there present, standing as spectators without the battle, seeing the armies now ready to join, could not but consider in themselves to what a pass private ambition and emulation had brought the empire. Common arms, and kindred ranks drawn up under the selfsame standards, the whole flower and strength of the same single city here meeting in collision with itself, offered plain proof how blind and how mad a thing human nature is when once possessed with any passion; for if they had been desirous only to rule, and enjoy in peace what they had conquered in war, the greatest and best part of the world was subject to them both by sea and land. But if there was yet a thirst in their ambition, that must still be fed with new trophies and triumphs, the Parthian and German wars would yield matter enough to satisfy the most covetous of honour. Scythia, moreover, was yet unconquered, and the Indians too, where their ambition might be coloured over with the specious pretext of civilizing barbarous nations. And what Scythian horse, Parthian arrows, or Indian riches could be able to resist seventy thousand Roman soldiers, well appointed in arms, under the command of two such generals as Pompey and Caesar, whose names they had heard of before that of the Romans, and whose prowess, by their conquests of such wild, remote, savage, and brutish nations, was spread further than the fame of the Romans themselves? To-day they met in conflict, and could no longer be induced to spare their country, even out of regard for their own glory or the fear of losing the name which till this day both had held, of having never yet been defeated. As for their former private ties, and the charms of Julia, and the marriage that had made them near connections, these could now only be looked upon as tricks of state, the mere securities of a treaty made to serve the needs of an occasion, not the pledges of any real friendship.
Now, therefore, as soon as the plains of Pharsalia were covered with men, horse, and armour, and that the signal of battle was raised on either side, Caius Crassianus, a centurion, who commanded a company of one hundred and twenty men, was the first that advanced out of Caesar's army to give the charge and acquit himself of a solemn engagement that he had made to Caesar. He had been the first man that Caesar had seen going out of the camp in the morning, and Caesar, after saluting him, had asked him what he thought of the coming battle. To which he, stretching out his right hand, replied aloud, "Thine is the victory, O Caesar, thou shalt conquer gloriously, and I myself this day will be the subject of thy praise either alive or dead." In pursuance of this promise he hastened forward, and being followed by many more, charged into the midst of the enemy. There they came at once to a close fight with their swords, and made a great slaughter; but as he was still pressing forward, and breaking the ranks of the vanguard, one of Pompey's soldiers ran him in at the mouth, so that the point of the sword came out behind at his neck; and Crassianus being thus slain, the fight became doubtful, and continued equal on that part of the battle.