Ellis ap Griffith

Ellis ap Griffith's arms, being those of Gwyddelwern, inherited from his grandfather Lord Tudor Glendower, from the maternal side
Harlech Castle, seat of his granduncle, Prince Owain Glendower, before losing the war against Shakespeare's "Prince Hal", historically known as Henry V
St Beuno church of Gwyddelwern

Ellis ap Griffith (c.1440 – 1489) or Elissau ap Gruffudd, was the Baron of Gwyddelwern in Denbighshire, Wales, and the grandnephew of Owen Glendower, Prince of Wales. Following his family defeat during the Glyndwr Rising, his branch inherited the co-representation of the Royal House of Mathrafal, and were immortalized by William Shakespeare in the history play Henry IV. Through his mother Lowrie, he inherited the lordship of his grandfather, Tudor Glendower, and by marriage, the estate of Plas-yn-Yale. By this union, he became the founder of the House of Yale, represented by the Yale family, later known in America as the benefactors of Yale University.