The Mound of Arberth; also the Throne, Chair or Gathering place of Arberth. (MW. Gorssedd. Modern spelling Gorsedd; mutates to Orsedd.)
The mystical starting point for the first encounter of Rhiannon and Pwyll, First Branch, episode 2. In the Third Branch, episode 2, Pryderi, his wife, Rhiannon and Manawyddan sit upon the Mound, and the devastation of Dyfed follows with considerable special effects.
Manawydan returns to Gorsedd Arberth with Cigfa, and farms three fields there. He then conducts a magical duel to restore Dyfed and reclaim the exiled Pryderi and Rhiannon.
(First published 28/07/2014: Shan Morgain)