During the excavation in Katsuren Castle in Okinawa Island (Japan) archeologist unearthed bronze and copper coins. With x-ray analysis scientist revealed that one coin dated in IV century AD from reign of Roman Emperor Constantine I.
On the obverse side of the coin scientist believed its a image of Emperor Constantine I. From the excavations in 2013. until today, researchers also discovered coins from period of Ottoman empire probably from 17. century AD. Katsuren Castle was known as trading point with China and other neighboring countries.
Until today, trading of these people with European empires were very little known. This is the first time in this area that scientist founding coin from period of Roman Empire. The distance between borders of Roman Empire and point of Katsuren Castle is approximately 8.000 kilometers away. Katsuren Castle probably build in 14 and 15 century AD.
So the main mystery is how this coins get there. Katsuren Castle was once the residence of a feudal lord, whose wealth was linked to regional trade. The ruins of this Castle were registered in 2000 on the World Heritage list.
Source: The Japan Times