In Pwyll Pendefig Dyfed, the first branch of the Mabinogi, Hefeydd Hen (or Heyfedd the Old[1]) was the father of Rhiannon.
[2] According to legend, Hefeydd Hen tried to force his daughter Rhiannon to be married against her will to Gwawl son of Clud.
She met Pwyll of Dyfed at the Mound of Arberth[2] and planned to marry at her father's court in one year and one day.
By a trick, Gwawl was captured and he and his men were defeated; forcing Hefeydd to allow Rhiannon to marry Pwyll in his court.
[4] Caeawg, the leader, armed was he in the noisy conflict; His was the foremost part of the advanced division, in front of the hosts.