Appian of Alexandria Civil Wars 2.2.9

[9] In the meantime Pompey, who had acquired great glory and power by his Mithridatic war, was asking the Senate to ratify numerous concessions that he had granted to kings, princes, and cities. Many senators, however, moved by envy, made opposition, and especially Lucullus, who had held the command against Mithridates before Pompey, and who considered that the victory was his, since he had left the king in a state of extreme weakness for Pompey. Crassus coöperated with Lucullus in this matter. Pompey was indignant and made friends with Caesar and promised under oath to support him for the consulship. The latter thereupon brought Crassus into friendly relations with Pompey. Thus these three most powerful men coöperated together for their mutual advantage. This coalition the Roman writer Varro treated in a book entitled Tricaranus (the three-headed monster). ¹ The Senate had its suspicions of them and elected Lucius Bibulus as Caesar’s colleague to hold him in check. ²