Even more important was his son GILBERT IV ( 1243 - 1295 ), ‘ the Red Earl ’ b. 2 Sept. 1243 ; his first wife was Alice de Valence , of the family which had succeeded the Marshals in the earldom of Pembroke . The Red Earl 's father and grandfather, absorbed in the baronial struggle with the Crown , had been somewhat negligent of a nearer menace to their fortunes in Wales — the rise of the principality of Gwynedd ; they had regarded the two Llywelyn s [i.e. Llywelyn the Great and Llywelyn the Last ] (qq.v.) merely as convenient allies against the Crown . Gilbert IV in his turn sided with Montfort , but after Lewes ( 1264 ) they quarrelled, and Montfort encouraged Llywelyn II to ravage Gilbert 's lands in Wales ; Gilbert therefore fought for the king at Evesham ( 1265 ). He then however again changed sides, and indeed was the chief author of the compromise of 1267 . In the same year was signed the treaty of Montgomery , which acknowledged Llywelyn as Prince of Wales and gave him (among other gains) the lordship of Brecknock . Llywelyn 's lands in Brecknock now marched with the Clare lands, and a further question arose — if Llywelyn was now (by the treaty) overlord of all the Welsh lords in Wales , was he overlord of the semi-independent Welsh lords of north Glamorgan ? Prince and earl spent 1268-9 endeavouring to reach a settlement (the king clearly was unable and probably unwilling to settle the matter); in the meantime, it is clear from the documents that Llywelyn was already treating the Welshmen of Higher Miskin (above what is today Pontypridd ) and Higher Senghennydd (above Gelli-gaer ) as willing vassals. Gilbert 's response to this was twofold. On the one hand, he imprisoned and exiled ( 1267 ) Gruffydd ap Rhys (great-grandson of Ifor Bach , q.v. ), the Welsh mesne lord of Senghennydd ; and it is probable that it was at this time that he took into his own hands also the Welsh mesne lordship of Glynrhondda . In the second place, he began building the great castle at Caerphilly ( 1268 ). Llywelyn rushed down ( Oct. 1270 ) and razed the castle; Gilbert began rebuilding it in June 1271 . It was agreed (Nov.) that a royal garrison should occupy the castle pending negotiations, but Gilbert 's men got inside it by stratagem — however, with the king's death this local quarrel was merged into the greater controversy between Llywelyn and the new king , Edward I .
Gilbert does not figure largely in the Welsh war of 1277 , but more is heard of him in that of 1282-3 . He was commander of the royal armies in west Wales , and led them into Carmarthenshire , but on 6 June 1282 was so signally defeated near Llandilo that he had to retreat, and to lose his command. Yet we find him in Jan. 1283 with the royal force which took Dolwyddelan castle (Caerns.) . When the king made a royal progress through Wales ( 1284 ), we note the ceremonious formalities which stressed the privileged position of a ‘ lord marcher ’ — Edward entered Glamorgan only after Gilbert 's formal consent, and Gilbert accompanied his in overlord from frontier to frontier. When Rhys ap Maredudd of Dryslwyn (q.v. in Appendix) revolted in 1287 , Gilbert was given large powers to put down the revolt, and indeed acted energetically — yet there were whispers that Rhys was to escape, with his connivance, to the Clare lands in Ireland .
Past events did not augur well for future good relations between the king and his over-powerful vassal . Ever since 1283 , Edward had been scheming to bind Gilbert more effectively to the royal cause: the earl was to divorce his wife and to marry the king's daughter Joan , so that his broad lands should descend to heirs more closely attached to the Crown . The pope took some time to facilitate this arrangement, and the marriage had to wait till 2 May 1290 — it was then further provided that should the marriage prove childless, the lands were to go to Joan 's children by a second marriage. In the meantime, trouble had broken out between Gilbert and his neighbour Humphrey Bohun VII ( c. 1250-98 ), lord of Brecknock (on the Bohuns , see D.N.B. and William Rees , ‘ The Mediaeval Lordship of Brecon ’ in Trans. Cymm. , 1915-16 ), because Gilbert had built a castle on their common boundary — on Brecknock land, so Bohun maintained; the castle was Morlais near Merthyr Tydfil (confused by some with Morgraig castle , between Caerphilly and Cardiff ). The king seized the opportunity of challenging the ‘marcher right’ to wage private war, and summoned the two lords to appear, first before a court of their peers in the March , and then (in view of the marchers’ disinclination to prejudice the ‘rights’ of their order) before their overlord the king's own court. Both lords were condemned to imprisonment and to the forfeiture of their lands during their lives. True, they were released almost at once, and their lands were restored. But the Red Earl 's prestige was gone. He d. 7 Dec. 1295 .
As had been provided, the Clare lands were enjoyed by the princess Joan for the rest of her life; she d. in March 1307 . Her marriage with the Red Earl had brought her three daughters and a son, GILBERT V ( 1291 - 1314 ), b. c. 10 May 1291 . The little that we know of his dealings with his Welsh tenants reflects favourably upon him: he seems to have depended much, in Glamorgan , on Llywelyn Bren ( Llywelyn ap Gruffydd , d. 1317 , q.v.) of the old Welsh ruling family of Senghennydd . But he fell on Bannockburn field , 24 June 1314 . An eventual partition of his lands ( 1317 ) gave Tonbridge , Gloucester , Newport , and Wentloog to his sister MARGARET , Clare and Usk to another, ELIZABETH (the foundress of Clare College , Cambridge ), and the lordship of Glamorgan to the third, ELEANOR . She m. HUGH DESPENSER , whose family retained the lordship till 1411 ; it passed afterwards to the NEVILLE family, earls of Warwick ; on the death of the ‘ Kingmaker ’ ( 1471 ) it came into the hands of the house of York, was taken over by Henry VII after Bosworth , granted by him to his uncle Jasper Tudor (q.v.) , and resumed by the king on Jasper 's death in 1495 . In 1536 , it became the nucleus of the new shire of Glamorgan .
Emeritus Professor Robert Thomas Jenkins, C.B.E., D.Litt., Ll.D., F.S.A., (1881-1969), Bangor
Published date: 1959