Dictionary of Welsh Biography

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TREVOR , JOHN ( II ) , bishop of S. Asaph (d. 1410 ).

He is known as John Trevor II in order to distinguish him from his namesake, who was bishop between 1346 and 1357 and with whom he is sometimes confused. Described in one place as Ieuan ap Llywelyn , he was probably a native of Trevor , near Llangollen , in Powys Fadog , and kinship with the well-known Denbighshire family of the Trevor s has been claimed for him, although there does not appear to be any warrant for this in the available pedigrees [see Trans. Angl. Antiq. Soc. , 1951 , 57 (f.n. 98)]. The first recorded reference to him is in 1386 when he is found holding the precentorship of Bath and Wells , an office which he continued to enjoy until 1393 . Meanwhile he had been elected bishop by the chapter of S. Asaph in 1389 , but having visited Rome and failing to secure papal confirmation of the appointment, he stayed on there as an official of the Curia . When a vacancy again occurred at S. Asaph in 1394 , Trevor was given the see by papal provision and took possession in the following year.

Trevor became at once prominent in the service of Richard II , acting as his ambassador in Scotland in 1397 , and just before the king's abdication in 1399 was rewarded with high secular office in Wales . But he was one of the first to desert the ill-fated monarch, who was actually made captive in Trevor 's own diocese, and it was the bishop himself who read the sentence of deposition in full Parliament . He continued prominent as a royal emissary and spokesman during the early years of the Lancastrian regime , and as late as 1403 , long after the Glyn Dŵr revolt had started, he is found deputising in Wales for prince Henry , afterwards Henry V . But suddenly towards the end of the following year he transferred his allegiance to Glyn Dŵr .

Though the facts of his career suggest that he was a typical self-seeking churchman of his age, it is to his credit that before he adhered to the patriot cause he had protested unavailingly in Parliament against high-handed treatment of his fellow-countrymen. His diplomatic experience , moreover (the Northumberland alliance of 1405 and the crucial decisions of the Pennal Assembly in 1406 owed much to his mediation and counsel), and his legal knowledge (he was a doctor in laws ) were of the highest value to Glyn Dŵr , a fact which appears to have been recognized by the other side when, in 1409 , the bishop is associated by name with Owain as one of the king's arch-enemies. He d. on 10 or 11 April 1410 , while on a mission to Paris , and was buried there, in the infirmary chapel of the abbey of S. Victor . He had at least one admirer (as bishop of S. Asaph during the years before the rebellion) for Iolo Goch composed a highly eulogistic poem (possibly two) in his honour.

There are strong grounds for concluding that Trevor was also the author of a well-known work on heraldry — the Tractatus de Armis , as well as of its Welsh version — and that he translated the life of S. Martin ( Buchedd Sant Marthin ) into Welsh (see B.B.C.S. , iv, 3, 4; v, 1). E. J. Jones has also suggested that the authorship of several historical works of the period may be attributed to him (see Speculum , xii, 196 et seq. ; xv, 464 et seq .).


  • Oxford Dictionary of National Biography ;
  • J. E. Lloyd , Owen Glendower / Owen Glyn Dwr (1931) ;
  • Browne Willis , A survey of the cathedral church of Bangor; and the edifices belonging to it … (1721) ;
  • Thomas , A History of the Diocese of St. Asaph ;
  • H. Lewis (ed.), Cywyddau Iolo Goch ac Eraill, 1350–1450 , 97-1;
  • The National Library of Wales Journal , 1941 , 93-6.


Professor Thomas Jones Pierce, M.A., F.S.A., (1905-1964), Aberystwyth

Published date: 1959