Dictionary of National Biography, 1885-1900/Morgan Mwynfawr
MORGAN Mwynfawr (d. 665?), regulus of Glamorgan, was the son of Athrwys ap Meurig ap Tewdrig (genealogies from Cymmrodor, ix. 181, 182, viii. 85), and may be the Morcant whose death is recorded in 'Annales Cambriæ' under the year 665 (ib. ix. 159). The charters contained in the 'Book of Llandaff' include a number of grants which he is said to have made to the church of Llandaff in the time of Bishops Oudoceus and Berthguin (Liber Landavensis, ed. Evans and Rhys, 1893, pp. 145, 148, 149, 151, 155, 156, 174). Other charters in the book of the time of Berthguin are attested by him (pp. 176, 182, 191), and an account is also given (pp. 152-4) of ecclesiastical proceedings taken against him by Oudoceus in consequence of his murdering his uncle Ffriog Though the Book of Llandaff' was compiled about the middle of the twelfth century (preface to the edition of 1893), at a time when the see was vigorously asserting disputed claims, it nevertheless embodies a quantity of valuable old material, and (details apart) is probably to be relied upon, in the general view it gives of the position of Morgan. He appears as owner of lands in Gower (p. 145), Glamorgan (p. 155), and Gwent (p. 156), and, since the latter two districts were afterwards ruled over by his descendants, was probably sovereign of most of the region between the Towy and the Wye.
It has been very generally supposed that Morgannwg a term of varying application, but usually denoting the country between the Wye and the Tawe (Red Book, Oxford edit. ii. 412; Cymmrodor, ix. 331) takes its name from Morgan Mwynfawr (Iolo MSS. p. 11). Mr. Phillimore, in a note to the Cymmrodorion edition of Owen's 'Pembrokeshire' (p. 208), suggests, however, that it is merely a variant of Gwlad Forgan [cf. art. on Morgan Hen], and that previous to the eleventh century the country was always known as Glywysing.
Morgan Mwynfawr, in common with many of his contemporaries, is a figure in the legends of the bards. He is mentioned in the ' Historical Triads ' as one of the three Reddeners (i.e. devastators) of the isle of Britain (Myvyrian Archaiology, 2nd edit. pp. 389, 397, 404) ; in the 'Iolo MSS.' (p. 11) he is said to have been a cousin of King Arthur and a knight of his court, while his car was reckoned one of the nine treasures of Britain, for 'whoever sat in it would be immediately wheresoever he wished' (Lady Charlotte Guest, Mabinogion, 1877 edit. p. 286).
[Liber Landavensis, ed. Rhys and Evans, 1893 ; Iolo MSS., Liverpool reprint.]