(Rawlinson MS. B. 464, f. 42; Owen and Blakeway, Shrewsbury, i. 181), was probably born in 1359; on 3 Sept. 1386 he was between twenty-seven and twenty-eight years old (Scrope and Grosvenor Roll, i. 254, ed. Nicolas). On his father's side he traced back his descent through the princes of Powys Vadog to Bleddyn ab Cynvyn. His father's name was Gruffydd Vychan, i.e. the Little, modernised into Vaughan (Gruffydd Llwyd in Pennant, Tour in Wales, i. 311, ed. 1778). This surname was doubtless to distinguish him from his father, Owain's grandfather, whose name was also Gruffydd, and who was the son of Madog, son of Gruffydd Vychan, son of Gruffydd of Bromfield [see Gruffydd ab Madog, d. 1269] (Bridges, Princes of South Wales, pp. 250–2). The lands of Glyndyvrdwy had long been in the family. Early in Edward II's time Gruffydd ab Madog (b. 1298) was married to Elizabeth, daughter of Sir John L'Estrange of Knockin, near Oswestry (Rot. Parl. i. 306), and the lordships and manors of Glyndyvrdwy and Sycharth were entailed on this couple and their heirs (ib. iv. 440). Glyndyvrdwy was in Edeyrnion and a part of the old shire of Merioneth. It included the valley of the Dee between Corwen and Llangollen. Sycharth, then within the Welsh marches, is now part of the parish of Llansilin, on the borders of Shropshire and the modern county of Denbigh. Owain claimed to be descended from the old line of north Welsh princes, and thence from Cadwaladr Vendigaid and the fabulous Brutus (see Owain's letter in Adam of Usk, pp. 69–71). He also claimed descent from the old houses of Deheubarth, and, through his mother Helen, from Llewelyn ab Gruffydd (Leland, Itinerary, v. 44; Pennant, i. 302; Harl. MS. 807, f. 94). It is pretty clear, however, that Llewelyn's legitimate stock died out in his daughters. Owain also possessed in South Wales the manors of Yscoed and Gwynyoneth, but his main influence was in the north. He derived a revenue of three hundred marks a year from his lands, and was thus among the few Welsh gentlemen of large estate. He had in the north two great houses, of which the chief was at Sycharth, which, by his hospitality, became known as a ‘sanctuary of bards.’ The poet Iolo Goch [q. v.] has left a glowing description of the splendour of this house (text and translation in Y Cymmrodor, v. 264–73; and another translation in Pennant, i. 305). It was called Saghern by the English (Ellis, Original Letters, 2nd ser. i. 11). Owain had another house of only less importance at Glyndyvrdwy itself (ib. i. 12). Owain had a younger brother named Tudor.
It was afterwards believed that great prodigies attended Owain's birth, and contemporaries thought that he had magic help in his struggle against the English. The story, often told, that at the time of his birth the horses in his father's stables were found standing in blood, is really told of Edmund Mortimer in all the original authorities (‘Annales Hen. IV’ in Trokelowe, p. 349; Walsingham, Hist. Angl. ii. 254; Cont. Eulogium Historiarum, iii. 398; Monk of Evesham, p. 179; Holinshed).
Owain became a student of English law at Westminster, and was perhaps called to the bar (‘juris apprenticius’ Ann. Hen. IV, p. 333). He remained a student of ancient deeds. He subsequently became squire to the Earl of Arundel, who had large estates in North Wales and was lord of Dinas Bran, the great fortress overlooking Llangollen, not far from Owain's estates (Cont. Eul. Hist. iii. 388; Capgrave, De illustribus Henricis, p. 110). In 1385 he served in the Scottish campaign of Richard II (Scrope and Grosvenor Roll, i. 254). He was summoned as a witness in the famous suit of Scrope and Grosvenor, and on 3 Sept. 1386 gave evidence at Chester in favour of Robert Grosvenor's right to wear the arms azure a bend or (ib. i. 254).
Arundel was a strong partisan of the popular party, and Owain subsequently took service with Henry of Lancaster himself, afterwards Henry IV (‘scutifer regi moderno,’ and therefore not of Richard II, as is generally said; Ann. Hen. IV, p. 333; Walsingham, ii. 246). His connections were therefore thoroughly Lancastrian and constitutional. Yet Wales in general was strongly attached to King Richard, and when Henry IV on his accession made his son Henry prince of Wales, the French metrical chronicler prophesied that the new prince would not gain the lordship without force (Archæologia, xx. 204). Tumults became common from the time of Richard's deposition. Prince Henry's council, under Henry Percy, the famous ‘Hotspur,’ had little success in restoring order.
One of Owain's strongest neighbours was Reginald, lord Grey of Ruthin [q. v.] with whose house the king's tenants in Glyndyvrdwy had long been in conflict. A dispute was now caused by Owain's claim to some land in Grey's possession. It is said by the continuator of the ‘Eulogium Historiarum’ (whose dates are often wrong) that Owain journeyed to Westminster to complain before the Hilarytide parliament in 1401 of Grey's usurpation (Cont. Eul. Hist. iii. 388). But Owain was already in arms in 1400. If the story be true, it must refer to the parliament of October 1399, but there is no record of the transaction in the ‘Rolls of Parliament.’ The