Ffernfael ab Idwal

Ffernfael ab Idwal or Ithel (died ) was a late 8th-century king of Gwent in southeast Wales. His name seems to mean "strong ankles". His father was Idwal or Ithel ap Morgan, (c. 690, reign 710–745), king of Glywyssing, Gwent, and Ergyng. Ffernfael's grandmother may have been Ricceneth, and he had an uncle named Gwyddnerth.

Ffernfael was the great-grandson of Athrwys ap Meurig and possibly Cenedlon ferch Briafael Frydig, and the great-great-grandson of King Meurig ap Twedrig and Onbrawst, daughter of Gwrgan Fawr, the last King of Ergyng. This is thought to be how Ergyng became part of the territorial holdings of the family.

Ffearnfael married Ceingaer as his queen. Ergyng (now in western Herefordshire in England) was apparently lost to the Saxon kingdom of Hwicce around this time. Alternatively, Ffernfael's brothers Rhodri and Rhys and his nephew Brochfael may have inherited in turn, but lost Gwent to Ffernfael for a time.

Ffernfael's death is recorded by the undated Annals of Wales. Phillimore's reconstruction places the entry in the year 775.

Children Athrwys, king of Gwent