Longterm formal diplomatic and trade relations with Arabia and Persia, at least insofar as you start seeing largescale foreign communities within China, really only began in the Tang Dynasty period following the turmoil of the mid-8th century. These foreign communities were, as later with the Ming, physically and legally segregated from the native populations in cities like Chang’an (Xi’an) and Guangzhou, but there is relatively known about them, owing to a relative dearth of primary sources, since the Chinese didn’t seem to have been particularly interested in recording much about their foreign populations at that time, save how they enhanced the prestige of their imperial court. The Book of Tang only mentions the Persians and Arabs once, and that is to document an alleged instance of them sacking and burning the city of Guangzhou (Canton) in 758, before returning to sea. This general outlook of Arabs as being untrustworthy bandits – unfortunately a product of the age, since the nation was then racked by the An Shi Rebellion, which managed to cement in the minds of the Han populace at large that idea. That was was likely one of the catalysts that sparked the Yangzhou Massacre of 760, which saw the rebel army of Tian Shengong, resulting in the death of several thousand foreign merchants.

The records of normalization of relations and longterm settlement really only come from one or two Arab sources, as recounted by Bretschneider:

The merchant Soleyman visited China around the middle of the ninth century. He went there by sea and landed at a town which he calls Kanfou, situated several days' journey from the sea. Renaudot and Deguignes believed he meant Canton, but Reinaud is of the opinion that Soleyman landed at Hang chou fu (in Chekiang). Another Arabian merchant, Ibn Vahab, visited and described China in 872 AD and was received by the Emperor. It appears from the relations given by these two travelers that the Arabs at that time carried on commerce with the Chinese by sea. The Chinese records do not mention this.

Nevertheless, by the end of the 8th century, it seems southern ports like Guangzhou may have boasted foreign populations of as many as 200,000 merchants, primarily from Arab and Persian territories. These foreigners were chiefly importers and exporters, and many had become tremendously wealthy from their business dealings in Tang China. Unfortunately for them, both their foreignness and their accumulated wealth would render them among the prime targets when in the late 9th century, as the Tang Dynasty spiraled down toward its eventual demise, their otherness would mark them out as scapegoats by th likes of Emperor Wuzong, and by 878 attract the rebel Huang Chao who would lead his bandit army south to plunder the trading port’s foreign quarter. Arab writer and contemporary of the event, Abu Zayd Hassan of Sirafi, wrote of the slaughter:

“Supplies to [Guangzhou from the Arab countries] have been cut off for it, the land has been ravaged, its customs have vanished, and its authority has been scattered […] The cause for the change of condition in China from what it […] was that there arose amongst them one outside the royal family, who was known as Banshu [Huang Chao]. His affairs began [with] cunning, [impetuous] youthfulness, the bearing of arms, mischief, and the assembling of rogues around him until trenchancy became intensified and his numbers multiplied. Then his greediness became obsessive and he headed for Khanfu [Guangzhou], one of the Chinese cities. […] Then the inhabitants opposed him and he besieged them for a long while […] until he triumphed over it. Then he put its inhabitants to the sword. And men experienced in their affairs have mentioned that he killed 120,000 Muslims, Jews, Christians, and Magians who lived in this city and became merchants in it, apart from those killed among the Chinese inhabitants. The amount of the numbers of these four sects was known only because of [their] taxation [by] Chinese people [according to] their numbers.”

The subsequent collapse of Tang authority in the 10th century and the fracturing of China into the so-called 5 Dynasties and Ten Kingdoms ground any notions of international trade or foreign settlement to a standstill, right up until the reunification of the entire realm under the Mongol Yuan Dynasty in the 13th century. The pan-asiatic nature of the Mongol Empire, as well as its implementation of the yassa system of laws across the lands of the former Silk Road saw overland east-west trade once again flourish for the first time since the Han Dynasty (Tang-era foreign trade was as already mentioned overwhelmingly naval, since the western reaches of the Silk Road were unable to be secured). But the Yuan extensively utilized non-Chinese foreigners as its semu caste (or more completely, 各色名目) of multi-ethnic officials from all across central and western Asia.

By the time of the collapse of the Yuan in the 14th century, Han Chinese and Muslim population had banded together against their Mongol overlords’ excessive cruelty and legal prohibition of their cultural habits (halal/kosher slaughter, for instance, was prohibited under the yassa, as was circumcision – a particular affront to the empire’s jewish population). When Zhu Yuanzhong, eventual founder of the Ming and Hongwu Emperor, rose up in the 1360s, for instance, one of his most trusted generals, Lan Yu, was a Muslim from the western reaches of modern Anhui.

Though some of the semu population was allowed to remain in China following the expulsion of the Yuan, the enforced assimilation of Chinese customs under the Hongwu Emperor, and the more widespread distrust of foreigners severely limited their numbers. Hongwu’s own edicts reflected this severe distrust of foreign influence of any kind, such as this on his epitaph:

Let the state be small and the people few;
So that the people [...] fearing death, will be reluctant to move great distances
And, even if they have boats and carts, will not use them.
So that the people [...] will find their food sweet and their clothes beautiful,
Will be content with where they live and happy in their customs.
Though adjoining states be within sight of one another and cocks crowing
and dogs barking in one be heard in the next,
Yet the people of one state will grow old and die without having had any
dealings with those of another.

The third Ming emperor, Yongle, famously relaxed such restrictions – at least insofar as he commissioned the voyages of Admiral Zheng He (himself an ostensibly-Muslim descendant of Yuan semu official Sayyid Ajjal Shams al-Din Omar) to announce to the world the greatness of the new Chinese order, and to establish control over the Indian Ocean trade routes (now once again the primary means of trade following the post-Mongol breakdown of the Silk Road). Following Yongle and Zheng He’s deaths, however, his successor, the Hongxi Emperor re-imposed and even exacerbated the Ming restriction on movement and foreign trade, as well as destroying the great Treasure Fleets and burning its records. Such a blanket ban would remain pretty much in place up through the fall of Ming and establishment of the Qing in the 17th century and into the 18th. The imperial worldview was summed up during the infamous McCartney Mission of 1793 which saw an ascendant Britain replace the anemic Portuguese presence in the South China sea with their own tea-and-crumpets version of global imperial ambition.