Mithridates has meanwhile forged a strong alliance of his son-in-law, Tigranes, under whom the country has become the strongest state in the Roman East.

At its height, the Armenian Empire extends from the Pontic Alps (in modern northeastern Turkey) to Mesopotamia, and from the Caspian Sea to the Mediterranean.

Tigranes, apparently invading territories as far away as Ecbatana, has taken the title king of kings which, at this time, according to their coins, even the Parthian kings do not assume.

He is called "Tigranes the Great" by many Western historians and writers, such as Plutarch.

The "King of Kings" never appears in public without having four kings attending him.

Cicero, referring to his success in the east, said that he "made the Republic of Rome tremble before the prowess of his arms.”