In the spring of 688 Pompeius proceeded to Galatia, to take the chief command of the troops of Lucullus and to advance with them into the Pontic territory, whither the Cilician legions were directed to follow.  At Danala, a place belonging to the Trocmi, the two generals met; but the reconciliation, which mutual friends had hoped to effect, was not accomplished.  The preliminary courtesies soon passed into bitter discussions, and these into violent altercation:  they parted in worse mood than they had met.  As Lucullus continued to make honorary gifts and to distribute lands just as if he were still in office, Pompeius declared all the acts performed by his predecessor subsequent to his own arrival null and void.  Formally he was in the right; customary tactin the treatment of a meritorious and more than sufficientlymortified opponent was not to be looked for from him.

Invasion of Pontus
Retreat of Mithradates

So soon as the season allowed, the Roman troops crossed the frontier of Pontus.  There they were opposed by king Mithradates with 30,000 infantry and 3000 cavalry.  Left in the lurch by his allies and attacked by Rome with reinforced power and energy, he made an attempt to procure peace; but he would hear nothing of the unconditional submission which Pompeius demanded—­what worse could the most unsuccessful campaign bring to him?  That he might not expose his army, mostly archers and horsemen, to the formidable shock of the Roman infantry of the line, he slowly retired before the enemy, and compelled the Romans to follow him in his various cross-marches; making a stand at the same time, wherever there was opportunity, with his superior cavalry against that of the enemy, and occasioning no small hardship to the Romans by impeding their supplies.  At length Pompeius in his impatience desisted from following the Pontic army, and, letting the king alone, proceeded to subdue the land; he marched to the upper Euphrates, crossed it, and entered the eastern provinces of the Pontic empire.  But Mithradates followed along the left bank of the Euphrates, and when he had arrived in the Anaitic or Acilisenian province, he intercepted the route of the Romans at the castle of Dasteira, which was strong and well provided with water, and from which with his light troops he commanded the plain.  Pompeius, still wanting the Cilician legions and not strong enough to maintain himself in this position without them, had to retire over the Euphrates and to seek protection from the cavalry and archers of the king in the wooded ground of Pontic Armenia extensively intersected by rocky ravines and deep valleys.  It was not till the troops from Cilicia arrived and rendered it possible to resume the offensive with a superiority of force, that Pompeius again advanced, invested the camp of the king with a chain of posts of almost eighteen miles in length, and kept him formally blockaded there, while the Roman detachments scoured the country far and wide.