Parthia (C. anxi guo 安息國) refers to a region in Central Asia southeast of the Caspian Sea. The region was known to the Romans as Parthia. However, according to the Princeton Dictionary, the region was known as Aršak by the Parthian rulers, and this name was used by the Chinese.
There is evidence of a Buddhist presence in Parthia from the second through the sixth centuries. This includes archeological evidence of Buddhist structures in the old Parthian city of Margiana from the fourth through sixth centuries.
- Parthia, Encyclopedia Britannica