This little musing was inspired by my viewing of Atlas today (keep reading for details).
In the very late 3rd century BC, the Han Dynasty came to power in China. The first lasting dynasty to rule a unified, the Han did all sorts of nation-building stuff, basically showing the next two millenia what it meant to be Chinese and powerful. One of the things they did over the next few centuries was to deal with their barbarian problem. Way off there somewhere to the West, along the Silk Road, were these other people who had exotic stuff and also a hankering for all sorts of everyday stuff they ignorantly seemed to regard as exotic and gosh, it sure would be nice to trade with them. So, after some internal debates (which make for fascinating reading, especially in light of 19th and 20th century arguments over industry versus agriculture and development), they put together a sucession of large armies and basically drove out the Xiongnu, the barbarians to the north of Han China. The Silk Road was open, and things were good.
Halfway around the world, a little pipsqueak pimple of a nation on the Mediterranean was brutally hacking and slashing its way to the top of the Largest Empire charts. As things turned out, the Pax Romana was pretty good for trade, even if you were just a conquered people rather than a Roman proper. And when various neat trade goods started flowing through the Parthians and other bizzare Asian nation-states out there to the East, the Romans were more than happy to take up their role as a trading partner with a massive economy. Provided some wealth to shore up the northern frontier, in fact, where the barbarians had been mostly contained in the German forests. There were those annoying Goths to deal with, but at least the Goths seemed mostly content to expand eastwards, rather than south into Roman turf.
Then, in the 5th century, right when things were getting pretty dicey for the Romans anyway, things all went to hell all at once. This insane warrior people calling themselves Huns came rolling out of the Ukraine, smashing into the Goths and driving southwest. The Goths, terrified and panicky, went rolling into the only turf open to them: the Western Roman Empire. The rest -- including Rome -- was history.
The punchline, of course, is that the Huns and the Xiongnu were one and the same. Their centuries-long migration started when they were driven away from China by the desire for trade. It ended when they encountered the other end of that cross-continental trade rout, and left substantial parts of it bleeding and/or on fire. Perspectives like this unified one were basically nonexistent at the time; it's taken our own, more gloabl, age to piece together the various narratives and find the common elements. I've been in awe ever since I first heard the story: it shows you how interconnected even the ancient world was. Rome and China barely understood each other's existence, and yet their trading connections fueled both their individual histories and the larger migrations of which they were only observers, set in motion events that radically affected the history of the human world entire. The world has always been smaller than it seems, perhaps.