Goronwy ab Ednyfed was one of the sons of Ednyfed Fychan, seneschal to Llywelyn the Great, Prince of Wales. Goronwy's mother, Gwenllian, was daughter of Rhys ap Gruffydd. When Llywelyn ap Gruffudd rose to power in the Kingdom of Gwynedd, he brought all three of Ednyfed's sons into his service. By 1258, Llywelyn had styled himself the Prince of Wales, the same year that Goronwy had been established as his seneschal. Goronwy continued in this role for the following ten years, during which time he was involved in a variety of negotiations with the Marcher Lords, with Richard, the Bishop of Bangor, and with several other Welsh princes. Goronwy led Llywelyn's troops as far south as Gwent to combat the Marcher Lords in February 1263. He died on 17 October 1268, and was remembered by Welsh chroniclers for his wisdom and integrity as well as his ability in arms. It is possible that Goronwy's name appears in a list of witnesses to a contract of Llywelyn the Great as early as 1222. Thus it is likely that he had served as a court official together with his father before succeeding him as seneschal of Gwynedd on his death in 1246, or in the years between 1222 and 1258. A single source tells us that another son of Ednyfed, Gruffudd, was seneschal of Gwynedd from 1246 to 1256. Thus there is some doubt about tha succession in that period. It is known with certainty that he was a witness to documents relating to Gwynedd between 1258 and 1268, under Llywelyn ap Gruffudd. As seneschal, he led a powerful force together with Maredudd ap Rhys, Rhys Fychan, and Maredudd ab Owain of Deheubarth against the Normans of Gwent and the forces of the king of England there in March 1263. The last reference to him in official documents is as an arbitrator between Llywelyn ap Gruffudd and Gilbert de Clare after a raid by Llywelyn on Morgannwg; it is dated 27 September 1268. Goronwy had land from his father in Anglesey, Arllechwedd and Ceredigion. Goronwy died on St Luke's Eve, 17 October 1268, according to the Brut y Tywysogion: "The following year Goronw son of Ednyfed, seneschal to the prince, died on the eve of St Luke the Evangelist, a man excellent in arms, generous with gifts, wise in counsel, loyal in deeds, and pleasant in words." The bard Y Prydydd Bychan composed an elegy to him. The text is very incomplete and adds very little to our knowledge of him. Another bard, Bleddyn Fardd, composed another elegy to him, which refers to the raid on Gwent and the losses which followed. His death so soon after the hostilities in Gwent suggests that he was wounded there, but there is no proof of this.
