The province of Cilicia was assigned to him, Bithynia to Cotta.

Mithradates invaded Bithynia, defeated Cotta, and besieged him at Chalcedon.
Lucullus, after reorganizing and disciplining his army, went to the aid of his colleague, drove the king into Pontus, and defeated him at Cabira in 72, and his fleet at Tenedos in 71, compelling him to take refuge with his son-in-law, TIGRANES, King of Armenia.
Lucullus endeavored to work reforms in the administration of provincial governments in the East.

The revenues of the provinces were farmed out, and the measures of Lucullus were intended to protect the tax-payers against the tax-gatherers (_publicani_).

His reforms met with bitter opposition at Rome, especially from the Equites, whose chief source of income was often this same tax-farming.

Intrigues against him by persons sent from Rome began to create dissatisfaction among his troops.