Plutarch, Brutus
Bernadotte Perrin, Ed.

4. Here, when the state was rent by factions, Pompey and Caesar appealing to arms and the supreme power being confounded, Brutus was expected to choose the side of Caesar, since his father had been put to death a while before at the instigation of Pompey;¹ but thinking it his duty to put the public good above his own, and holding that Pompey's grounds for going to war were better than Caesar's, he attached himself to Pompey. [2] And yet before this he would not even speak to Pompey when he met him, considering it a great abomination to converse with the murderer of his father; now, however, looking upon him as his country's ruler, he put himself under his orders, and set sail for Cilicia as legate with Sestius, to whom the province had been allotted. [3] But since there was nothing of importance for him to do there, and since Pompey and Caesar were now about to meet in a supreme struggle, he came of his own accord into Macedonia to share the danger. It was then, they say, that Pompey was so filled with delight and admiration that he rose from his seat as Brutus approached, and in the sight of all embraced him as a superior. During the campaign, for whatever part of the day he was not with Pompey, he busied himself with books and literature, not only the rest of the time, but even before the great battle.² [4] It was the height of summer, the heat was great (since they had encamped in marshy regions), and they that carried the tent of Brutus were slow in coming. But though he was thus all worn out, and though it was almost noon before he anointed himself and took a little food, nevertheless, while the rest were either sleeping or occupied with anxious thoughts about the future, he himself was busy until evening in making and writing out a compend of Polybius.