Gruffudd landed on Anglesey with an Irish force, and with the assistance of troops provided by the Norman Robert of Rhuddlan first defeated and killed Cynwrig ap Rhiwallon, an ally of Trahaearn who held Llŷn, then defeated Trahaearn himself in the battle of Gwaed Erw in Meirionnydd and gained control of Gwynedd.
Llanfihangel-y-Pennant is a small village and community, which includes Abergynolwyn, in the Meirionnydd area of Gwynedd in Wales.
Born at Trawsfynydd, Meirionnydd, Jones he was educated at the local school, then, with scholarships, proceeded to Friars School, Bangor and Christ College, Brecon, and then Jesus College, Oxford, where he gained a first class degree in divinity in 1886, an MA and BD in 1907 and a DD in 1914.
S. Baring-Gould in The Lives of the British Saints (1907) states that he was the son of Cedig ap Ceredig ap Cunedda Wledig, and that his mother was a Saint Tegfedd or Tegwedd, the daughter of Tegid the Bald (Tegid Foel), Lord of Penllyn in Meirionnydd, and that he lived in the early part of the 6th century.