The latter identification led Pelliot to propose that it transcribed the name of Alexandria in Egypt, of which more will be said below.” Pulleyblank (1999), p. in the Hànshū which I believe is of doubtful authority in this case] could be said to resemble ‘Hyrcania’, it is a far cry to the original ‘Vehrkāna [i.e., Old Persian Wrkāna]” (1979: 118).
In fact the sequence –rkan is common to both the Greek and the Old Persian and fits well with EMC lεj/li x This is the standard and most natural pronunciation found, for example, in the Takigawa edition and the recent Zhónghuá shūjū edition.
Therefore I have translated Da Qin as either ‘Rome’ the city, ‘Roman territory,’ or the ‘Roman Empire,’ as the context demands. on the southwest  corner of the Caspian Sea; and that, surprisingly, it is Tiaozhi that is a good transcription of Seleukia.
The reader should remember, meanwhile, that in each case the Chinese text will have only ‘Da Qin’.“It becomes clear that, as first proposed by Brosset (1828) and accepted by a number of other scholars, including Markwart, De Groot, and Herrmann (1941), Líjiān is actually a transcription of Hyrcania, Old Persian Wrkāna, a country that existed in the second century B. The difficulty with identifying Líjiān with Hyrcania is that, although it fits perfectly with the earliest account in the Shĭjì, the name was displaced when the passage was copied into the Hànshū and in later texts it reemerges as another name for Dà Qín.
Yu (1998) believes Daxia [dat-hea] stands for the Tochari (pp. Hirth, and many other scholars who followed him, have taken Da Qin to refer to the ‘Roman Orient.’ I think that the term is often clearly used in a broader sense than this to mean the Roman Empire, or any territory subservient to Rome.