The local mayor is pushing the story these days for political reasons, so every once in a while a story like this makes it to the press: Roman descendants found in China? - Telegraph.
Aurel Stein was an early explorer of Afghanistan, Central Asia and western China. He brought back a couple of Roman coins he bought in Central Asia to the British Museum, but he bought them from a dealer he describes as 'dodgy' and at least one comes from a coin 'hoard' that recent research suggests was put together in modern times. More interesting is the item illustrated here, which he bought in western China: Gold imitation of a Byzantine coin found in China. A number of real and imitation gold coins were excavated in Gansu province, some found in the mouths of the deceased - mostly they were found in the tombs of Zoroastrian non-Chinese merchants living in the area.
We can be more specific than the BM web site about the coins these days thanks to excavations that have found the Byzantine coins and their imitations in context - I'll be blogging more about them soon - but for now I'll simply quote what the BM says about this coin:
From the Astana cemetery, near Turfan, north-west China, 6th century AD
A treasured coin from the west
Gold imitations of Byzantine solidi have been found at various sites in China, mostly in the tombs of wealthy people in northern China, buried between the fourth and eighth centuries AD. It is likely that the coins were treasured prestige items of the rich.
Gold coins are mentioned in written documents found in the tombs of the Astana cemetery. For example, burial lists of the mid-sixth to mid-seventh centuries outlining the contents of the tomb often refer specifically to gold coins. Despite this, actual gold coins are not often found in the tombs, so it may be that the lists were wishful thinking.
It seems that the practice of including real or imagined gold coins in tombs was only common for about one hundred years as earlier documents refer to gold by weight rather than to coins, and later documents simply list 'sufficient gold and silver'.
Diameter: 16 mm Weight: 0.85 g
Marc Aurel Stein Collection
CM BM Stein [IA.XII.c.1]
Room 68, Money, case 5, panel 4, no. 48
World of Money CD-ROM (London, British Museum Multimedia, 1998)
H. Wang, 'The Stein collection of coins from Chinese Central Asia' in K. Tanabe, J. Cribb and H. Wang (eds.), Studies in Silk Road coins and culture: papers in honour of
Professor Ikuo Hirayama on his 65th birthday (Kamakura, Institute of Silk Road Studies, 1997), pp. 187-99
M.A. Stein, Innermost Asia: detailed report of exploration in Central Asia, Kansu and Eastern Iran, 4 vols. (Oxford, 1928, reprinted New Delhi, 1981)
F. Thierry, 'Sur les monnaies sassanides trouvées en Chine', Res Orientales, 5 (1993), pp. 89-139
F. Thierry and C. Morrisson, 'Sur les monnaies byzantines trouvées en Chine', Revue Numismatique, 6th series, 36 (1994), pp. 109-45