The theory that Polo went to Persian and his fable is an amalgam of Persian travellers' tales was thoroughly discussed in “Did Marco Polo Go to China?” by Frances Wood. Because Wood discussed theories, there were other scholars who disagreed with her and argued Polo had gone to China. Another scholarly discussion ... then Japanese archaeologists announced they had found Kublai Khan's lost fleet - see here:
Kenzo Hayashida of the Kyushu Okinawa Society for Underwater Archaeology (KOSUWA) found the seal above, which proves the ship was Mongol, and these ceramic shells which confirm the use of grenades in the written sources as early as 1221.
The problem is that Kublai Khan tried to invade Japan twice, in 1274 and in 1281, and Marco Polo, supposedly an eye-witness, kinda confuses the two events, mixing up incidents from one in the account of the other that he "saw" ... He also described the Mongol ships as having five masts, when archaeology proves they only had three ...
So did Marco Polo go to China sometime between 1271 and 1295? Probably not, but who cares - lots of others did.
Perhaps the best known traveller to China was the Franciscan monk William of Rubruck because he left extensive writings about his visit to the Mongol capital Karakorum in 1254 - here. When he got to Karakorum he found that there were Christians there, mostly Nestorians, and a Church where he was able to celebrate Easter with some other Western Catholic Christians (here):
[we] passed through the Saracen quarter, where there is a square and a market, to the church. And the Nestorians came to meet us in a procession. Going into the church, we found them ready to celebrate mass; and when it was celebrated they all communicated and inquired of me whether I wished to take communion. I replied that I had already drunk, and could not receive the sacrament except fasting. When the mass had been said it was already after noon, so master William took us with great rejoicing to his house to dine with him; and he had a wife whose father was J of Lorraine, but born in Hungary, and she spoke French and Coman well. We found there also another person, Basil by name, the son of an Englishman, and who was born in Hungary, and who also knew these languages. We dined with great rejoicing, and then they led us to our hut, which the Tartars had set up in an open space near the church, with the oratory of the monk.China and the West since the Classical period. Sources record Alopen arriving in Xi'an in 635 and establishing a Nestorian church. Whether the Daqin Pagoda in Xi'an was a Nestorian church before it became a Buddist temple is debated, but a stele erected there in 781 survives and details, in Chinese and Syriac, the story of the Nestorians in China. The stele is headed with the description "Memorial of the Propagation in China of the Luminous Religion from Daqin" ...
Daqin was the Chinese name for the west, as seen on the Sihai Huayi Zongtu map of 1532 - (I've circle it in red for those that don't read Chinese):
Gan Yang had been sent by the Emperor of China to Rome in AD 97, but he only got as far as Persia, so his account it probably of as little use as Marco Polo's. As he pointed out: "The king of this country always wanted to send envoys to the Han, but Anxi [Parthia], wishing to control the trade in multi-coloured Chinese silks, blocked the route to prevent [the Romans] getting through [to China]"
The Romans called China Serres or Serica; the Chinese called the Roman Empire Daqin or Lijian, and thought that the capital was the great city of Antu (Antioch). The Byzantine Empire at Constantinople was Fulin. Several accounts are gathered here, and detail the last Byzantine embassy in the Chiu-t'ang-shu:
The emperor Yang-ti of the Sui dynasty [AD 605-617] always wished to open intercourse with Fu-lin, but did not succeed. In the 17th year of the period Cheng-kuan [AD 643], the king of Fu-lin Po-to-li [Constans II] sent an embassy offering red glass, lu-chin-ching [green gold gems], and other articles. [Emperor] T'ai-tsung favored them with a message under his imperial seal and graciously granted presents of silk.Also recorded in the 13th century Ma Tuan-lin, Wen-hsien-t'ung-k'ao, which records some later contact:
During the tenth month of the fourth year of the period Yuan-feng [November 1081 C.E.] their king Mieh-li-i-ling-kai-sa [Michael Caesar, of Cilicia] first sent the ta-shou-ling [a high official] Ni-si-tu-ling-si-meng-p'an to offer as tribute saddled horses, sword-blades and real pearls.
During the sixth year of Yuan-yu [1091 C.E.] they sent two embassies, and their king was presented, by Imperial order, with 200 pieces of cloth, pairs of silver vases, and clothing with gold bound in a girdle.(My favourite part of the Chronicle is the fascination with the queens of Meroe: "There is also a report that in the west there is the country of women ... It is further said: the country of Mo-lin [ 'Alwa, or Upper Nubia]")
Numerous Chinese chronicles document contact with the West, and although none mention Marco Polo several mention other embassies from Western Europe in the Medieval period. From the Ming-shih, ch. 326 covering AD 1368-1643:
At the close of the Yuan dynasty [1278-1368 C.E.] a native of this country, named Nieh-ku-lun, came to Zhongguo for trading purposesNieh-ku-lun seems to be Nicolaus de Bentra, who succeeded as Archbishop of Peking in 1333.
Marco Polo may not have reached China, but many Western Christians did. Giovanni da Pian del Carpine was a follower of Francis of Assisi sent by Innocent IV in 1245 on an embassy to Karakorum, the Mongol capital. Giovanni arrived there in 1246, failed to convert the Great Khan, and returned in 1247 with a letter for the pope. His report, the Ystoria Mongalorum, survives and includes the letter; a report by his companion Benedict of Poland, the De Itinere Fratrum Minorum ad Tartaros, also survives. Another embassy was sent the same year with Ascelin of Cremona and Simon of St Quentin carrying letters from the pope translated into Persian. The Dominican André de Longjumeau went first to Mongolia in 1245 with letters from the pope, then again in 1249 with gifts from Louis IX. William of Rubruck was sent in 1253 by Louis IX, and went with Bartolomeo of Cremona and Abdullah, a translator. The popes were so happy with their reception that they sent Franciscan missionaries: in 1289 Nicholas IV sent John of Monte Corvino to Beijing and in 1307 Clement V appointed him Archbishop, with a church opposite the imperial palace.
These were all missionaries, whose primary aim was to convert the Mongols and Chinese to Christianity. There were also many merchants who, unlike Marco Polo, really did make it to China, but who were too busy trading to write fantastical accounts of the country. The AD 870 Kitāb al-Masālik w’al- Mamālik of
Ibn Khordadbeh, the oldest surviving Arabic geography book, is a good source of information about the Radhanites (pp. 2-3 here), Jewish merchants who traded actively between western Europe and China. Jews were barred from certain professions once the west had become Christian, so they turned to trade, using a common language as an advantage that allowed them to communicate anywhere they met another Jew. There is however no textual or archaeological evidence for Jews in China before the Tang Dynasty, when they were amongst those massacred by Huang Chao according to the Xin Tang Shu.
The Radhanites flourished under Charlemagne, who used them as translators on embassies to Persia, until the time of the First Crusade when the rise of anti-Semitism in the West led many Jews to flee France and Germany to Eastern Europe, Spain and North Africa. Slavery was still common in the west, but since Jews were forbidden sell another Jew, a number of slaves converted to Judaism. Although the Radhanites are credited with several innovations, such as bringing paper to Europe, their most lasting legacy was the introduction by Joseph of Spain of Arabic numerals - which is why today we count 1 - 2 - 3 not I - II - III ...