The Armenian–Parthian War (87 to 85 BCE) refers to when the armies of Tigranes the Great victoriously entered Northern Mesopotamia and the kingdoms of Osroene and Atropatene pledged their loyalty and support to Tigranes the Great. Many rulers and kings labeled Tigranes, the great "Kings of Kings" because of his wealth and power.
The kingdoms of Osroyene and Atropatene pledged their loyalty and support to Tigranes the Great. In 85, the Parthians officially recognized him as the supreme ruler of the East. Tigranes took the hailed title of King of Kings, from the Parthian monarch, and honorably held it to the end of his life.