At the entrance gate of Abermarlais Park there is an interesting stone, near which, according to a tradition related to me by Mrs. De Rutzen, the Welsh Princes held a council or* war. I was also informed by people in the neighbourhood that the spot was once haunted by the ghost of a lady in white.
*sic. From 'Folk-lore of west and mid-Wales' by J C Davies (1911).
This message board for Llangadog http://www.llangadog.com/messageboard1.html
has a photo of the stone and describes how it is also known as the 'Bosworth Stone', having been allegedly brought home from Bosworth Field by Sir Rhys Ap Thomas, as a souvenir of his side's victory (Abermarlais was one of his homes).