Question: Who is the paternal grandfather of Iorwerth Drwyndwn?
Sentence (from "Owain Gwynedd"): Owain ap Gruffudd (23 or 28 November 1170) was King of Gwynedd, North Wales, from 1137 until his death in 1170, succeeding his father Gruffudd ap Cynan.
Relevant evidence: Yes