Dictionary of National Biography, 1885-1900/Iestin ab Gwrgant
IESTIN ab Gwrgant (fl. 1093), prince of Gwent and Morganwg, is a shadowy hero of the legend of the conquest of Glamorgan, whose biography, as told in the 'Gwentian Brut y Tywysogion,' is fabulous and absurd.
Married in 994, he failed to obtain the succession of Morganwg on his father's death in 1030, because the people preferred his great-uncle, Howel ab Morgan [q. v.]; but he became ruler on Howel's death in 1043. Nearly fifty years later he is said to have taken a prominent share in the history of the conquest of Glamorgan by the Normans. He was an enemy of Rhys ab Tewdwr, the king of Brecheiniog. Hard pressed by his enemy, he promised to marry his daughter to Eineon ab Collwyn [q. v.] if the latter could procure him help from England against their common foe Rhys. Eineon obtained the help of Robert Fitzhamon [q.v.], who speedily defeated and slew Rhys, king of Brecheiniog. We know from authentic history that Rhys died in 1093. Iestin paid the Normans liberally and they went their way. He now refused his daughter to Eineon, saying that he would never give either land or daughter to a traitor. Eineon in revenge persuaded Fitzhamon to return. The Normans soon became masters of Iestin's territory and drove Iestin away, Iestin fled to Glastonbury over the Channel; thence he went to Bath and finally back to Gwent, where he died at the monastery of Llangenys at an extraordinarily old age. His sons, Caradog, Madog, and Howel, abandoned their father to his fate and were rewarded with a share of the conquered land, Caradog, the eldest, obtaining the lordship of Aberavon.
The details of the story of the conquest of Glamorgan are mythical; the outline is not in itself unlikely. [For a critical examination of the story see Eineon, son of Collwyn, and Fitzhamon, Robert]. Iestin's historical existence is proved by the existence of his descendants. His grandsons, Morgan, Maredudd, Owain, and Cadwaladr, the four sons of Caradog were joint lords of Aberavon when Archbishop Baldwin and Giraldus Cambrensis made their crusading tour in Wales (Giraldus Cambrensis, Itin. Cambriæ, in Opera, vi. 69, 72, Rolls Ser.) Rhys, another son of Iestin, is also mentioned in a document of the reign of John (Dugdale, Monasticon, v. 259). Some Glamorganshire families claim descent from Iestin (cf. 'the Lords of Avan of the blood of Iestin,' in Archæologia Cambrensis, 3rd ser. xiii. 1-44; and G. T. Clarke, Limbus Patrum Morganiæ et Glamorganiæ, 1886).[Brut y Tywysogion (Cambrian Archæol. Assoc. 1863); Freeman's William Rufus,ii. 80-2, 87, 614; other authorities are given in the articles on Eineon, son of Collwyn, and Fitzhamon, Robert.]