Experts believe rare 12th Century slate inscriptions found on a castle were probably made to protect against evil.

The dozen scratchings were uncovered during a three-week excavation at Nevern in Pembrokeshire.

Archaeologists think the stars and other designs were made by a serf, labourer or soldier some time between 1170 and 1190 when the castle was built.

They say they also give an insight into the beliefs of medieval working men.

© UnknownExperts believe the scratchings were made by a peasant some time between 1170 and 1190
Dr Chris Caple of the University of Durham led the archaeological dig at the site and said the slates were from a late 12th century cut-stone entranceway.

"They were found in only one place in the castle and were probably intended to ward off evil," he explained.

"In the late 12th century, Nevern would have been an impressive looking castle and entrance, especially from the south side, and it was clearly visible to all passing along the road between St David's and Cardigan.

"The work under way on the slates will no doubt provide more fascinating information about the beliefs and ideas of the people who built and lived in the castle."

Work is under way cleaning, revealing and recording the images and further research is being carried out by the university's department of archaeology.

Phil Bennett, the Pembrokeshire Coastal National Park Authority's head of archaeological heritage, said it was hoped to keep the slates in Nevern.

"These drawings connect us with the lives and beliefs of masons or labourers who built the castle.

"We hardly ever recover evidence about the peasants of the medieval world, and never information about their beliefs and ideas, but these scratched designs are from the imagination of a serf, a farm labourer or a man at arms."

© UnknownIt was the fourth year that the site has been excavated
The dig also unearthed information about the phased building of parts of the castle and revealed that a round tower thought to have imprisoned Lord Rhys in 1194 was also the quarters of high status members of the castle household.

It was the fourth year that the site has been excavated in a partnership project between Dr Caple, the National Park Authority, Dyfed Archaeological Trust and Nevern community council which owns the site.