This book draws on a wide variety of evidence to reevaluate the rapidly changing international environment of Western Asia from the 110s to the 50s BCE, challenging traditional Rome-centric perspectives of the geopolitical developments of this period to emphasize the agency and actions of the powerful kings and kingdoms in Western Asia. Although the Parthians and Romans emerged as hegemons over their respective international environments in the second century BCE, with the Parthian Empire centered on the Iranian plateau and the Roman Empire of the Republic centered on the Mediterranean, the bounds of their geopolitical interests and international perspectives began to overlap in Western Asia in the 90s BCE. In the 80s BCE, the Kingdom of Pontus, under the leadership of Mithridates VI, suddenly emerged as an aggressive hegemonic rival to Rome in the West, and the Kingdom of Armenia, under the leadership of Tigranes II, suddenly emerged as an aggressive hegemonic rival to Parthia in the East.Overtoom completely reconsiders the interactions of Parthia, Rome, Pontus, and Armenia in the chaotic, violent, and evolving international environment of Western Asia in this period, where the Parthians and Romans struggled to maintain authority within their separate spheres of influence into the 70s and 60s BCE. Furthermore, this study demonstrates that, in the 90s to the 60s BCE, the Parthians and Romans rarely interacted, preferring informal and distant relations that were neither combative nor collaborative.