Pyers Gruffydd of Penrhyn
- Buried: Westminster Abbey, London, Midlesex, England
Another name for Pyers was Piers Griffith.
From The History of the Princes, the Lords Marcher, and the Ancient Nobility of Powys Fadog, and the Ancient Lords of Arwystli, Cedewen, and Meirionydd by J. Y. W. Lloyd, Vol. IV (London, 1884), p. 342:
"He married Margaret, d. of Sir Thomas Mostyn of Mostyn, Knt. He bought and fitted out a ship at his own expense, and was present at the defeat of the Spanish Armada. He also accompanied Drake and Raleigh in a subsequent expedition against the Spaniards, and was subsequently obliged to mortgage his estate of Penrhyn, which was sold to the mortgagees in 1616. In 1622 it was purchased by his cousin, John Williams, Archbishop of York, Lord Keeper of the Great Seal in 1620, a descendant, through a female, from its former possessors. Pyers Gruffydd was buried in Westminster Abbey. The mortgagees were Ieuan Lloyd, Esq., and Sir Richard Trevor."