Experts are examining carvings on an old wooden chair that shows evidence of having been immersed in sea water for some time.
The seat is stored in the Am Fasgadh building at the Highland Folk Museum in Newtonmore in the Cairngorms.
Thought to date from the 17th or 18th Century, it was given to the museum by a donor from Edinburgh.
On the panel that forms the back of the seat are carved a lion and a unicorn on a crest with a crowned heart motif.
The museum believes the carvings may refer to the Clan Douglas, whose strongholds included cliff-top Tantallon Castle, near North Berwick.
Soldiers loyal to Oliver Cromwell sacked the castle in 1651 and many of the items inside were thrown into the sea below the castle.
Museum staff have been working with the Regional Furniture Society to discover more about the chair.
Images of the carved panel have also been sent to heraldic authority, The Court of the Lord Lyon in Edinburgh, in the hope of indentifying the crest.
Image copyrighted to Highland Folk Museum.