So I'm reading "The Civil War" by Lucan and in one passage very early on he mentions "Ere this the Chinese might have passed under our yoke, and savage Araxes, and any nation that know's the secret of Niles cradle".
Now I'm aware that Rome and Han China would have been aware of each other existence. What I am wondering is how much would they know of each other. Lucan was a poet, so would the average Roman patrician know who the Chinese are? Or was this a translation error of some kind?
They would know of China, but very little, in brief.
The Romans and the Chinese both knew the other existed, and both of them had more extensive commercial relations with intermediary states between them. Both made efforts to contact one another: the Chinese diplomat Gan Ying is famous for having traveled farthest to the west of any Han chinese person in classical antiquity. He reached either the Red or Black sea before (possibly) Parthians discouraged him from continuing. However, Chinese geographers were able to include Alexandria, the Nile delta, and the western shores of the Mediterranean in the extremes of their cartography.
As far as their worldview went, Romans knew China existed, and they knew it was a vast and wealthy empire. Beyond that, they knew little: it's possible they were aware of the Yellow River, but China was essentially the end of the world in the Roman imaginings. There are varied inscriptions in Pliny about the topic; they suggest very little. Roman geographers generally distrusted merchants and foreigners and didn't appear to take too much of what they had to say to heart.
Chinese records, strangely, suggest multiple Roman envoys arriving at several points in history; however, there are no surviving records of these envoys to be found in Roman history. It's possible men arrived claiming to be Roman ambassadors, but were in fact not Roman or not ambassadors; it's also possible that Roman records of such a mission were simply lost. Given the distance between their worlds and their reliance on intermediaries in central Asia for any commerce, the two empires had relatively little to actually gain from one another.
Roman patricians come in many forms, and lack a coherent "averageness." Some were wealthy, some were not; however, it was considered part of a father's duty as Pater Familia to ensure that his children were educated to their station. For a family of decent means and noble blood, that would absolutely include the study of geography, likely with a rhetor, the most advanced teachers in the Roman system.
So, to put it short: A Roman waxing poetic would certainly be able to mention the Chinese. In that context, he would be speaking of the most exotic, mysterious land possible: to muse about conquering it, he would be contemplating not just the conquest of the known world, but even regions almost wholly unknown.
Which book was this in? I wasn't able to find it.