This name has been traced as Welsh origin but is still today quite uncertain. The meaning seems to be "marrow famous, eminent", probably from “mer” (marrow) plus “myn” (eminent). Merfyn Frych was King of Gwynedd from around 825 to 844, the first of its kings known not to have descended from the male line of Cunedda. Precious little is known of Merfyn's reign. Thornton suggests that Merfyn was probably among the Welsh kings who were defeated by Ecgberht, king of Wessex, in the year 830, but it is unknown how this affected Merfyn's rule.