King Phraates III of Parthia succeeded his father Sanatruces

Sanatruces of Parthia

King Sanatruces of Parthia ruled the Parthian Empire from c. 77 to c. 70 BC. He was a member of the Arsacid house, who, according to work attributed to Lucian, in the troubled times after the death of Mithridates II in ca...

 and ruled the Parthian Empire

Parthia

Parthia is a region of north-eastern Iran, best known for having been the political and cultural base of the Arsacid dynasty, rulers of the Parthian Empire....

 from 70 to 57 BC. He was called "the God" because of his coins, that were ideal for sailors because they were polished with gold dust, so that people from other countries considered their value higher than their actual value.

When Phraates III came to the throne in 70 BC, the Roman general Lucullus

Lucullus

Lucius Licinius Lucullus , was an optimate politician of the late Roman Republic, closely connected with Sulla Felix...

 was preparing to attack Tigranes the Great

Tigranes the Great

Tigranes the Great was emperor of Armenia under whom the country became, for a short time, the strongest state east of the Roman Republic. He was a member of the Artaxiad Royal House...

, king of Armenia

Armenia

Armenia , officially the Republic of Armenia , is a landlocked mountainous country in the Caucasus region of Eurasia...

, who was supreme in western Asia and had wrested Mesopotamia

Mesopotamia

Mesopotamia is a toponym for the area of the Tigris–Euphrates river system, largely corresponding to modern-day Iraq, northeastern Syria, southeastern Turkey and southwestern Iran.Widely considered to be the cradle of civilization, Bronze Age Mesopotamia included Sumer and the...

 and several vassal states from Parthia. Naturally, Phraates declined to assist Mithradates VI of Pontus and Tigranes against the Romans. Instead, he supported his son-in-law, the younger Tigranes, when he rebelled against his father, and invaded Armenia in 65 BC in alliance with Pompey

Pompey

Gnaeus Pompeius Magnus, also known as Pompey or Pompey the Great , was a military and political leader of the late Roman Republic...

, who abandoned Mesopotamia to the Parthians. But the desperate Pompey soon overrode the pompous treaty; he acknowledged the elder Tigranes, took his son prisoner, occupied the vassal states Gordyene and Osroene

Osroene

Osroene, also spelled Osrohene and Osrhoene and sometimes known by the name of its capital city, Edessa , was a historic Syriac kingdom located in Mesopotamia, which enjoyed semi-autonomy to complete independence from the years of 132 BC to AD 244.It was a Syriac-speaking kingdom.Osroene, or...

 for the Romans, and denied the title of "king of kings," which Phraates had adopted again, to the Parthian king. About 57 BC Phraates was murdered by his two sons, Orodes II

Orodes II of Parthia

Orodes II of Parthia ruled the Parthian Empire from 57 to 38 BC. Orodes was a son of Phraates III, whom he murdered in 57 BC, assisted by his brother Mithridates...

 and Mithridates III

Mithridates III of Parthia

King Mithridates III of Parthia ruled the Parthian Empire c. 57–54 BC. With the assistance of his brother Orodes he murdered his father Phraates III. He was made king of Media and waged war against his brother, but was soon deposed on account of his cruelty. He took refuge with Aulus Gabinius, the...

.