Plutarch, Lucullus
Bernadotte Perrin, Ed.

30. Here he received an embassy from the king of the Parthians also, inviting him into friendly alliance. This was agreeable to Lucullus, and in his turn he sent ambassadors to the Parthian, but they discovered that he was playing a double game, and secretly asking for Mesopotamia as reward for an alliance with Tigranes. [2] Accordingly, when Lucullus was apprised of this, he determined to ignore Tigranes and Mithridates as exhausted antagonists, and to make trial of the Parthian power by marching against them, thinking it a glorious thing, in a single impetuous onset of war, to throw, like an athlete, three kings in succession, and to make his way, unvanquished and victorious, through three of the greatest empires under the sun.

[3] Accordingly he sent orders to Sornatius and his fellow commanders in Pontus to bring the army there to him, as he intended to proceed eastward from Gordyené. These officers had already found their soldiers unmanageable and disobedient, but now they discovered that they were utterly beyond control, being unable to move them by any manner of persuasion or compulsion. Nay, they roundly swore that they would not even stay where they were, but would go off and leave Pontus undefended. [4] When news of this was brought to Lucullus, it demoralised his soldiers there also. Their wealth and luxurious life had already made them averse to military service and desirous of leisure, and when they heard of the bold words of their comrades in Pontus, they called them brave men, and said their example must be followed in Gordyené, for their many achievements entitled them to respite from toil and freedom from danger.