The military campaigns of Tigranes the Great, the king of Greater Armenia from 95 to 55 BCE, consisted of offensives against client kingdoms of the Roman Republic and Parthian Empire. His conquests extended the realm from the Caspian Sea in the east to the Mediterranean Sea in the west, encompassing territories such as Syria, Phoenicia, and parts of Anatolia (modern-day Turkey). He built a new capital, Tigranocerta, and populated it with people deported from Cappadocia. His initial invasions of Cappadocia drew the attention of the Roman Republic, and after being defeated in two separate campaigns, Tigranes was allowed to keep Armenia as a client kingdom of Rome while paying an indemnity of 6,000 talents and relinquishing all his conquests.
Background
In 120 BCE, Tigranes was taken as hostage, following his uncle Artavasdes' defeat by Mithradates II, king of Parthia. By 95 BCE, Tigranes had inherited the kingdom of Armenia from his father and secured his freedom by surrendering seventy valleys to the Parthians. In 91 BCE, Mithradates II, king of Parthia, died and Gotarzes I, his son, took over as ruler. During his reign, the Parthian Empire was divided by civil war, while Rome was preoccupied with the Social war, to which Tigranes expanded his territory by the conquering and annexing former client-kingdoms.
Campaigns
Campaign of 95 BCE
Tigranes invaded Sophene around 95 BCE. He either deposed the king of Sophene, Artanes, and fully annexed the territory, or left Artanes as a client-king.
Campaign of 91–90 BCE
In 91-90 BCE, Tigranes was persuaded by his father-in-law, Mithridates VI Eupator, to attack the Roman client kingdom of Cappadocia. Ariobarzanes, king of Cappadocia, fled to Rome ahead of Tigranes' army, while a treaty between Mithridates and Tigran gave Cappadocian cities and lands to the former and its population and movable property(spoils) to the latter. In response, Roman general Sulla occupied Cappadocia, forced out and killed many Armenians and disloyal Cappadocians, and re-installed Ariobarzanes as client-king of Cappadocia. Despite Sulla's invasion, Tigranes was able to unite the eastern province of Cappadocia, Melitene, with Sophene.
Campaign of 88–85 BCE
From 88 to 85 BCE, Tigranes retook the seventy valleys, given to the Parthian Empire for his freedom, located in Atropatene. He invaded and occupied Adiabene, Gordyene, and Media-Atropatene, and according Nina Garsoïan his forces advanced as far as Ecbatana. According to Manandian, Tigranes did, however, burn Adrapana, a fort 10 kilometers from Ecbatana.
Campaign of 84–83 BCE
In 84-83 BCE, Tigranes annexed Cilicia Pedias, Mygdonia, Osroene, and Commagene. Mithridates I Callinicus, king of Commagene, would continue to rule, although as a vassal. Mithridates' son, Antiochus I, would inherit Commagene from his father and continue as a client-king until the Roman offensive of 69 bce. Tigrane oversaw the resettlement of Arabs from southern Mesopotamia into Osroene, Edessa specifically.
In Syria, the constant civil war between the Seleucids, and recent death of its ruler in 84 BCE, had prompted an appeal for Tigranes to accept the throne. The conquest of Syria by Tigranes was bloodless, and Aleppo maintained its independence as a city-state. One of Tigran's generals, Magadates, was appointed governor of the newly constituted province of Syria that most likely included Cilicia. The king's brother Guras was put in charge of the significant Mesopotamian city of Nisibis.
According to some primary sources, Tigranes campaign advanced as far as Egypt, while secondary sources indicate that his armies only reached northern Palestine.
Campaign of 78 BCE
Acting on the news of Sulla's death, Tigranes invaded Cappadocia, again, this time deporting 300,000 of its people to his capital Tigranocerta. This raised the population of Tigranocerta to 500,000 people.
Aftermath
Tigranes' empire stretched from the Caspian Sea to the Mediterranean Sea, yet his conquests were short-lived. After the Romans had defeated his father-in-law, Mithridates VI Eupator in 70 BCE, Tigranes would be defeated in two separate campaigns. This freed the kingdoms of Iberia, Albania and Media Atropatene from Armenian hegemony, while Adiabene and Mesopotamia were returned to their local rulers. In 66 BCE, the Roman general Pompey allowed Tigranes to become a client-king of Rome and keep Armenia, after paying a war indemnity of 6,000 talents and relinquishing all provinces and kingdoms taken in his previous campaigns.