A RARE Roman coin with its images of a warlike emperor went on display yesterday.

The bronze penny, which is about an inch and a half in diameter, had lain undisturbed for about 1,800 years.

Archaeologists discovered it during a dig at Arbeia Roman Fort, in South Shields, South Tyneside.

The coin, traditionally carried by soldiers to bring luck, was buried under the main Roman road leading to the fort, which was built in 208 AD.

It depicts Emperor Trajan, a warrior and a favourite emperor among Roman soldiers, who celebrated the anniversary of his birthday for hundreds of years after his death.

Alex Croom, curator of archaeology at Arbeia, said: "Coins showing Trajan were popular among Roman soldiers. They tend to be found very worn, because they were in circulation for such a long time. This one is so unusual because it has kept its detail so well."

The coin had been in circulation for nearly 100 years before it was placed, or lost, on the roadway.

One side has a portrait of Trajan, while on the other is a detailed scene of the emperor addressing his troops.

Experts believe it could have been placed under the road deliberately, to bring the garrison at Arbeia good fortune.

"Trajan was seen as a good general and a solid soldier," said Ms Croom.

"These coins acted like amulets for normal soldiers, who carried his image because they hoped some of his good qualities would rub off on them."