He was soon followed by Pompeius, and the great pitched battle of the year took place on the plains of Thessaly. The two sides were far from being evenly matched; probably Pompeius had 40,000 legionaries and 3000 cavalry, while under Cæsar there were 30,000 legionaries and 2000 horse. When the armies came in sight of one another, there was some preliminary manœuvering to get the advantage of a favorable position, but finally Pompeius advanced some distance from his camp on level ground, and Cæsar, who was about to march away rather than attack under unfavorable conditions, decided to give battle. Pompeius’ right wing rested near a brook with precipitous sides. Relying on this to protect his flanks, he placed the light-armed infantry and the cavalry, under the command of Labienus, on the left wing with directions to make a vigorous onslaught on the troops opposed to them. If the enemy gave way, they were then to attack the legionaries on the sides and rear; in the meantime, Pompeius’ own legions were ordered not to advance but to await, where they were, the attack from the other side. It was hoped that Cæsar’s men would be in confusion before the hand-to-hand conflict began, as the distance they would have to traverse was greater than was usual in the battles of this period. Probably all of Cæsar’s cavalry were disposed in such a way that they faced the opposing cavalry. In order to compensate for his inferiority of numbers in this arm, he had trained some of his best legionaries to fight interspersed with the cavalry, after the practice among the Germans. The cavalry were separated, too, by a division of 3000 men, and behind his whole order of battle there was a considerable reserve force. It was to be supposed that, even without the assistance of this last support, his seasoned veterans would withstand the enemy for a long time. This expectation was all the more likely to be realized, just because of Pompeius’ orders that his own infantry were to be held back from engagement and should maintain their own ground, while his cavalry were at work. The battle opened with the cavalry charge on the Pompeian side. Cæsar’s German and Gallic horse, as they were instructed, withdrew, and as soon as the Pompeian horse followed them, the 3000 men placed previously to support them, attacked the Pompeian cavalry in the flank. This manœuver was immediately followed by a quick action on the part of Cæsar’s cavalry. They swerved about, attacked in their turn those who had just been pressing them, and forced them back in confusion. There was not time enough for Pompeius now to get together a mass of infantry to protect his cavalry. The hand-to-hand conflict immediately began, Cæsar’s whole force of infantry throwing themselves on the opposing legionaries, who now no longer had the support of their cavalry. The pressure on the front and sides was too much for the Pompeians; first the left wing gave way and then the entire army. (August 8, 48 B.C.)