In addition to the Mongols, Turks, et alia, Alexander the Great made it all the way to the Oxus River, and introduced Hellenic cultural modes to Central Asia, influencing even Buddhist art over the centuries (apparently). The silk trade from China was already lively during the Roman Empire—so much so that Pliny (the Elder or the Younger? I can’t recall) lamented the decadence of importing luxury goods from far-flung places like China and Africa.

And further west, there’s the critical role Arab scholars around the Mediterranean played during the Middle Ages, preserving the knowledge of ancient Greece and Rome, which would plant the seeds of the Renaissance when the Arabic translations of all these ancient works were translated back into Latin in late middle-age Spain, and disseminated throughout Europe.

Apparently a number of Korean men working in the Middle East on construction jobs in the 1970s and 80s converted to Islam. Maybe they were some of those.