Which you maybe already knew (I did, but only in a vague sort of way, and the fact that Ptolemy's Geographia mentions China and Japan). But I haven't actually read the source text for the Chinese side, the Weilüe (魏略), until today, thanks to io9:
There's a lot more to be found at the site (and the notes are awesome), but one thing I found interesting is that they called Rome Da Qin (or Ta-Ch'in)--meaning essentially that Rome, being the other large empire at the other end of the known world, was The Other China.
The kingdom of Da Qin (Rome)1 is also called Lijian.2 It is west of Anxi (Parthia) and Tiaozhi (Characene and Susiana), and west of the Great Sea.3
* * *
The ruler of this country is not permanent. When disasters result from unusual phenomena, they unceremoniously replace him, installing a virtuous man as king, and release the old king, who does not dare show resentment.18The common people are tall and virtuous like the Chinese, but wear hu (‘Western’) clothes. They say they originally came from China, but left it.19
They have always wanted to communicate with China but, Anxi (Parthia), jealous of their profits, would not allow them to pass (through to China).20
There's a lot more to be found at the site (and the notes are awesome), but one thing I found interesting is that they called Rome Da Qin (or Ta-Ch'in)--meaning essentially that Rome, being the other large empire at the other end of the known world, was The Other China.