I'd say the Chinese have been fairly separate from the West, with 3 primary peaks in power (Han dynasty, Tang-Song, and Ming-Qing), with perhaps a 4th (PRC) on

I'd say the Chinese have been fairly separate from the West, with 3 primary peaks in power (Han dynasty, Tang-Song, and Ming-Qing), with perhaps a 4th (PRC) on the way. So there's been at least two separate hegemons. But in the West it's hard to say when one hegemon is different to another. The Romans spoke a different language from the Greeks, took over by conquest but let the Greek language be spoken in their empire, until the Greek-speaking Eastern Roman (Byzantine) empire "evolved" from the Roman Empire. So you could say the Greeks ruled for 2000 yrs from Alexander the Great (400BC) to the fall of Constantinople to the Turks (1500AD), though the Romans ran things for 500-odd years in the middle. So there's certainly many complications.