Parthia ［安息国］ ( Ansoku-koku): An ancient empire of Asia. It was known in China as An-hsi. Established in the mid-third century b.c.e., the Parthian Empire lasted for about four and a half centuries. At its greatest extent it spread from northwestern India or Bactria in the east, encompassing the entire region between the Caspian Sea in the north and the Persian Gulf in the south, and extending to the Euphrates River and Armenia in the west. An Shih-kao and An Hsüan, who engaged in translating Buddhist scriptures into Chinese in second-century China, are known to have been natives of Parthia; the “An” in their names is an abbreviation of An-hsi, the Chinese name for Parthia.