Question: Who is the paternal grandfather of Iorwerth Drwyndwn?
Sentence (from "Iorwerth Drwyndwn"): Iorwerth ab Owain Gwynedd (or Iorwerth Drwyndwn meaning "the flat-nosed"), also called Edward (c. 1130–1174), was the eldest legitimate son of Owain Gwynedd (the king of Gwynedd) and his first wife Gwladys (Gladys)
Relevant evidence: Yes