The Silk Road was a network of markets and trading posts throughout Asia and the Indian Ocean Basin that extended from the eastern Mediterranean to the interior of China, and it earned its name thanks to the most valued commodity on the route: silk. Because of the large number of travelers making their way down the road, the different cultures that came into contact on the route, and the luxury goods that were being exchanged, intimacy on the historical Silk Road was an interesting, complicated, and nuanced cluster of encounters.
Silk had been exchanged for centuries, but the Han Dynasty in China officially opened its trade in silk (and other commodities) to the West in 130 BCE. Contact between Romans and the Han – and all groups in between – allowed for cultural and commercial exchange on an enormous scale. The Silk Road was used for over 1,500 years with varying popularity, reaching its height under the Mongols during the 13th and 14th centuries.
The merchants, diplomats, travelers, and missionaries who traveled along the Silk Road rarely traversed the whole route but rather participated in a relay system. Mostly men, these individuals copulated on the Silk Road, naturally, but over the extensive land mass and lengthy time period that the Silk Road was used, ideas about copulation, sexuality, and gender varied. This was not a bad thing, however, because there was a lot of influence and exchange that affected such practices and principles for the better. From cathouses and paid intimacy to how-to manuals and genetics, the blending of influences that informed carnality along the Silk Road had a little something to offer to everyone.
According to Marco Polo, when travelers stayed at the house of a stranger, the host was often willing to let the visitor sleep with his wife.
Polo wrote that when a traveler arrived:
the host is delighted, and desires his wife to put herself entirely at the guest's disposal, whilst he himself gets out of the way, and comes back no more until the stranger shall have taken his departure. The guest may stay and enjoy the wife's society as long as he lists, whilst the husband has no shame in the matter, but indeed considers it an honour. And all the men of this province are made wittols of by their wives in this way. The women themselves are fair and wanton.
Marco Polo indicated that the Mongols were not particularly thrilled about this activity, but they left the men to their shame and their "naughty custom."
Roman attitudes about slaves, sex workers, and concubines were not always clear, and intimate relationships between male owners and female slaves were common. In the Byzantine Empire, women sold themselves into sex work to survive, and, despite the modest Byzantine disposition, copulation was the preoccupation of many.
With the importance of silk in the Byzantine Empire, the Silk Road was traversed by Byzantine traders who had extensive contact with other merchants. Cathouses were present throughout the Empire, which was the western terminus of the Road.
During the early days of the Silk Road, Roman influences were heavy, particularly on the western end. As a result, Roman ideas about same-sex relationships were extended along some of its length. The history of male companionship in the Mediterranean is long and storied, but historians find that the Mongols engaged in homosexuality in China as well as in the Russian khanates. There are accounts of Ghenghis Khan, whose given name was Temujin, sleeping under blankets with other men, and while this doesn't mean they were in an intimate relationship, it's impossible to know either way.
That said, in the Mongol world, there was a heavy Islamic influence, which tended to perceive homosexuality as an improper subject in polite society, but also tended to accept encounters between two people of the same gender as part of one's private life.
Eunuchs were commonly used as diplomats and court officials by the late Roman and Byzantine Empires, as well as by Chinese dynastic leaders. After castration, a eunuch could be a hot commodity for a merchant within both empires. Perceived as neutral and harmless men, eunuchs often received privilege and prominence in social and political settings.
In China, eunuchs were similarly deemed unthreatening and found their way into the closest and highest imperial circles. Zheng He, a renowned Chinese explorer was eunuch, and he used his contact and influence to extend Chinese dynastic influence across the Silk Road.