Plutarch, Pompey
Bernadotte Perrin, Ed.

68. But notwithstanding, by their importunities and agitations, after they had gone down into the plain of Pharsalia, they forced Pompey to hold a council of war, where Labienus, the commander of the cavalry, rose first and took an oath that he would not come back from the battle unless he routed the enemy; then all likewise swore the same oath. [2] That night Pompey dreamed that as he entered his theatre the people clapped their hands, and that he decorated a temple of Venus Victrix with many spoils. On some accounts he was encouraged, but on others depressed, by the dream; he feared lest the race of Caesar, which went back to Venus, was to receive glory and splendour through him; and certain panic tumults which went rushing through the camp roused him from sleep. [3] Furthermore, during the morning watch a great light shone out above the camp of Caesar, which was perfectly quiet, and a flaming torch rose from it and darted down upon the camp of Pompey; Caesar himself says he saw this as he was visiting the watches.¹ At break of day, Caesar was about to decamp and move to Scotussa, and his soldiers were taking down their tents and sending on ahead the beasts of burden and servants, when the scouts came in with a report that they saw many shields moving to and fro in the enemy's camp, and that there was a noisy movement there of men coming out to battle. [4] After these, others came announcing that the foremost ranks were already forming in battle array. Caesar, therefore, after saying that the expected day had come, on which they would fight against men, and not against want and hunger, quickly ordered the purple tunic to be hung up in front of his tent, that being the Roman signal for battle. [5] His soldiers, on seeing this, left their tents with shouts of joy, and hurried to arms. And when their officers led them to the proper place, each man, as if in a chorus, not tumultuously, but with the quiet ease which training gives, fell into line.