Merfyn Frych, also known as Merfyn ap Gwriad and Merfyn Camwri, was King of Gwynedd from around 826 to 844, the first of its kings known not to have descended from the male line of King Cunedda.

The Harleian genealogies are a collection of Old Welsh genealogies preserved in British Library, Harley MS 3859. Part of the Harleian Library, the manuscript, which also contains the Annales Cambriae