Researchers are working to uncover the mysteries of 33 wood carved medallions which would have decorated the Royal Palace at Stirling Castle.

Historic Scotland is trying to find out why the works, known as the Stirling Heads and carved between 1530 and 1544, were created and whom they depict.

The carvings are thought to feature monarchs such as James V and England's Henry VIII.

The research is part of £12m plans to refurbish Stirling's Royal Palace.