If the favourable opportunity was to be employed, and Armenia was to be dealt with in earnest, Lucullus had to begin the war, without any proper orders from the senate, at his own hand and his own risk; he found himself, just like Sulla, placed under the necessity of executing what he did in the most manifest interest of the existing government, not with its sanction, but in spite of it.

His resolution was facilitated by the relations of Rome towards Armenia, for long wavering in uncertainty between peace and war, which screened in some measure the arbitrariness of his proceedings, and failed not to suggest formal grounds for war.
The state of matters in Cappadocia and Syria afforded pretexts enough; and already in the pursuit of the king of Pontus Roman troops had violated the territory of the great-king.

As, however, the commission of Lucullus related to the conduct of the war against Mithradates and he wished to connect what he did with that commission, he preferred to send one of his officers, Appius Claudius, to the great-king at Antioch to demand the surrender of Mithradates, which in fact could not but lead to war.
Difficulties to Be Encountered The resolution was a grave one, especially considering the condition of the Roman army.

It was indispensable during the campaign in Armenia to keep the extensive territory of Pontus strongly occupied, for otherwise the army stationed in Armenia might lose its communications with home; and besides it might be easily foreseen that Mithradates would attempt an inroad into his former kingdom.

The army, at the head of which Lucullus had ended the Mithradatic war, amounting to about 30,000 men, was obviously inadequate for this double task.