As Rome continued to push militarily and diplomatically eastward during the 90’s BCE, they eventually arrived near the Upper Euphrates to discover that many of the mini-kingdoms were in fact Parthian client states, especially Armenia. Once Rome officially discovered and understood the sphere of influence Parthia had over its western neighbors, Rome gradually took that model and began to court the eastern kingdoms subject to Parthian influence. However, before they can accomplish this, they must first meet their equals.
Around 92 BCE, their first diplomatic meeting took place. The relationship between both empires started peacefully. As time went on, tensions began to grow over the control of the Near East. While Parthia’s sphere of influence dominated the region, Rome’s political push at Parthia’s client states slowly caused a rift between the two powers that eventually led to war when Crassus invaded Parthia and was obliterated with his Roman forces at the Battle of Carrhae in 53 BCE. After Carrhae, their relations would never be the same, as both sides would continue a tug of war with the kingdoms between their borders, at times directly engaging each other.