Appian claims that Lucullus had embarked from Rome with only a single legion; upon entering Anatolia to make war against Mithridates, he added four more legions to his army. The overall size of this force consisted of 30,000 infantry and 1,600 cavalry.Appian. The Mithrdatic Wars, . Following Mithridates' retreat to Armenia, Appian estimates Lucullus' invading force to be only two legions and 500 horsemen,Appian. The Mithrdatic Wars, . although it is highly improbable that he would have undertaken the invasion of Armenia with such a small army.Ueda-Sarson, Luke. Tigranocerta: 69 BC. June 20, 2004. Accessed June 12, 2008. Plutarch gave 16,000 heavy infantry and 1,000 cavalry, slingers and archers for the Romans at Tigranocerta. Of these, 6,000 heavy infantry did not participate in the battle.Plutarch. Life of Lucullus, 27.2. Eutropius put the Roman army at 18,000 men.Eutropius 6.9 Historian Adrian Sherwin-White places the size of Lucullus' force at 12,000 seasoned legionaries (composed of three legions), and 4,000 provincial cavalry and light infantry.Sherwin-White, "Lucullus, Pompey, and the East," p. 240. The Roman army was further bolstered by several thousand allied Galatian, Thracian, and Bithynian infantry and cavalry, giving it a possible strength of 40,000.
