Although Orontes II is not mentioned very often in our sources, he appears to have been quite an important figure in the history of Armenia. He was probably appointed as satrap of Armenia by Darius III Codomannus, who had been ruler of this satrapy before he became king of the Achaemenid Empire in 336 BCE. It is possible that Orontes II was a descendant of the Orontes who had taken part in the Revolt of the Satraps (c.361 BCE) and had lost his throne.
The Greek-Roman historian Arrian of Nicomedia mentions Orontes II as one of the two commanders of the Armenian troops during the battle of Gaugamela (the other commander was Mithraustes),note[Arrian, Anabasis 3.8.5.] in which Alexander the Great defeated his Persian rival Darius III Codomannus (331 BCE). After his victory, Alexander sent his lieutenant Mithrenes to Armenia,note[Arrian, Anabasis 3.16.5.] but apparently, Orontes II remained in control of his satrapy.
In the Second Diadoch War, which was fought from 318 to 316 BCE between the successors of Alexander, an Orontes is mentioned as a supporter of Peucestas.note[Diodorus, World History 19.23.3; Polyaenus, Stratagems 4.8.3 tells the same story.] It is likely that this is Orontes II. The first leader of autonomous Armenia and the founder of the Orontid Dynasty may have died soon after. Perhaps Orontes III, who is mentioned in about 280 BCE, was his son or grandson.