The Dictionary of Welsh Biography reports, “Owain Dwnn's claim to be recognized as a poet is based chiefly on the contest of englynion between Gruffudd ap Nicholas, Owain Dwnn, and Gruffydd Benrhaw (the oldest text of which is to be found in Mostyn MS. 131 (59-78)), but it is difficult to judge their authenticity. There is another poem (englyn proest) also which is attributed to Owain Dwnn in Mostyn MS. 131 (510).”2524