The Romans were famous for their long roads which famously led right back to their imperial capital.

Now it's been suggested that the influence of the world's most famous empire may have stretched further than any ancient workman could have imagined.

2 This is one of the coins which was found in Japan, just under 10,000km away from Rome Credit: URUMA BOAR OF EDUCATION

2 A Roman coin which shows the face of Marcus Aurelius (stock image)

Astonished archaeologists have discovered an ancient cache of Roman coins in the Japanese city of Okinawa.

"I couldn't believe they'd found coins from the Roman empire in Kasturen castle," Hiroyuki Miyagi of Okinawa International University told CNN.

"I thought that they were replicas that had been dropped there by tourists."

But the coins turned out to be genuine and dated back to between 300 and 400AD.

Diggers discovered a total of 10 coins near Katsuren Castle in the town of Uruma, including some from the Ottoman Empire.

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"We don't think that there is a direct link between the Roman empire and Katsuren castle, but the discovery confirms how this region had trade relations with the rest of Asia," said Masaki Yokou, a spokesperson from Uruma city's Board of Education.

Archaeologists are now planning to examine the coins as well as the pottery found alongside them to understand why the currency turned up in such an unexpected place.

"The Chinese ceramics and coins that we found date back at least 600 to 700 years and we'd like to analyze those objects in tandem with these coins to work out how the coins may have ended up here," Miyagi added.