Uther Pendragon in John Boorman's "Excalibur"
Although I am confident of my identification of Uther Pendragon with St. Illtud, the question remains: was he really Arthur's father?
Information on Uther prior to Geoffrey of Monmouth's fictional HISTORY OF THE KINGS OF BRITAIN is scarce. To quote from the entry on Uther in P.C. Bartram's A CLASSICAL WELSH DICTIONARY:
UTHR BENDRAGON, father of Arthur. (445) ‘U. Chief Warleader’. Evidence that Uthr Bendragon was known to the Welsh before the time of Geoffrey of Monmouth is plentiful, but it does not tell us much about the pre-Geoffrey legend. He is mentioned in the poem ‘Who is the porter’ in the Black Book of Carmarthen, a dialogue between Arthur, Cai and Glewlwyd Gafaelfawr. Mabon ap Modron, one of the companions of Arthur, was guas Uthir Pendragon, ‘Servant of Uthr Bendragon’ (BBC 94, ll.6-7). An early triad (TYP no.28) tells of the Enchantment of Uthr Bendragon as being one of the ‘Three Great Enchantments’ of Ynys Prydain, and says that he taught the enchantment to Menw ap Teirgwaedd. In the Book of Taliesin (BT 71) there is a poem entitled Marwnat Vthyr Pen to which Dragon has been added in the margin in a later hand. This expansion is probably justified, since, among much that is obscure, the poem contains a reference to Arthur: ‘I have shared my refuge, a ninth share in Arthur's valour’ (BT 71, 15-16). See AoW 53. All these references bring Uthr into the Arthurian orbit (TYP p.521). Madog ab Uthr is mentioned in the Book of Taliesin (BT 66) and Eliwlod ap Madog ab Uthr is described as nephew of Arthur in a poem which shows no dependence on Geoffrey of Monmouth. See s.nn. Eliwlod, Madog. This is evidence that Uthr was regarded as father of Arthur in pre-Geoffrey legend. In two manuscripts of the Historia Brittonum (Mommsen's C, L, 12th and 13th centuries), §56, which lists Arthur's battles, contains a gloss after the words ipse dux erat bellorum: Mab Uter Britannice, id est filius horribilis Latine, quoniam a pueritia sua crudelis fuit, ‘In British Mab Uter, that is in Latin terrible son, because from his youth he was cruel’. According to Professor Jarman there is here a deliberate pun on the word uthr, which can be either an adjective (‘terrible’) or a proper name. The author of the gloss could have been familiar with Geoffrey of Monmouth's ‘Historia’. See A.O.H.Jarman in Llên Cymru, II (1952) p.128; J.J.Parry in Speculum, 13 (1938) pp.276 f. See further TYP pp.520-3.
The most important phrase in this entry is "This is evidence that Uthr was regarded as father of Arthur in pre-Geoffrey legend." The context is the 'Dialogue' poem. Unfortunately, as Professor Patrick Sims-Williams discusses in his "The Early Welsh Arthurian Poems" (in THE ARTHUR OF THE WELSH), the 'Dialogue' is preserved only in fourteenth century or later MSS., but may be as early as the twelfth century. Geoffrey of Monmouth wrote his HISTORY c. 1138, i.e. in the first half of the 12th century. Thus there is no way we can know whether the 'Dialogue' poem was influenced by Geoffrey's claim that Arthur's father was Uther Pendragon.
The reference to Arthur in the Uther elegy is, like many lines of this poem, difficult and obscure. Here are the relevant lines and accompanying note from Marged Haycock's recent translation:
13. Neu vi a rannwys vy echlessur:
It was I who shared my stronghold:
14. nawuetran yg gwrhyt Arthur.
Arthur has a [mere] ninth of my valour.
Note to Line14
nawuetran yg gwrhyt Arthur
Nawuetran ‘ninth part’ with yg gwrhyt understood as ‘of my valour’ (gwryt ~ gwrhyt). Arthur has a ninth part of the speaker’s valour. This seems to have more point than ‘I have shared my refuge, a ninth share in Arthur’s valour’, TYP3 513, AW 53. Gwrhyt ‘measure’ is not wholly impossible — ‘one of the nine divisions [done] according to the Arthurian measure/fathom’, etc., or ‘a ninth part is in [a place] called Arthur’s Measure or Span’, the latter like Gwrhyt Kei discussed TYP3 311, and other Gwryd names discussed G 709-10. The phrase is exactly the same as in §18.30 (Preideu Annwfyn) tra Chaer Wydyr ny welsynt wrhyt Arthur.
This is no way implies Arthur is Uther's son. As I've mentioned before, Arthur here may be the usual paragon of military virtue to whom Uther is being compared, much as the warrior Gwawrddur is compared (unfavorably) to Arthur in Line 972 of the "Goddodin." Yet someone like Geoffrey of Monmouth may have come across this 'death-song' and decided to use it as the exceedingly slender basis for making Uther Arthur's father.
Nothing in the VITA of St. Illtud suggests that he was Arthur's father. In fact, it is pointedly stated in that hagiographical work that Illtud is Arthur's cousin. So if Illtud were Arthur's father, the fact was later altered in the tradition which preferred to make of this terrible warrior a Christian saint.
All in all, the evidence in support of Uther as Arthur's father is quite poor. Yet if we dispense with him, we are left with no father at all for Arthur. We must admit that either his father was unknown or that the identify of his real father was, for some reason, concealed.