The problem with this idea, I just realized, is that in the Anglo-Saxon Chronicle genealogy for the Gewessei, Gewis is the father of Elesa (= Elafius). While there is evidence that the ASC reversed the pedigree for Cunedda and his sons, here is no reason to believe that Elesa was part of this reversal, nor that St. Constantitus of Lyons, who wrote the Life of St. Germanus, made the same mistake.
Here is the text and modern English translation of the relevant portion of the saint's vita again:
Meanwhile evil spirits, flying over the whole island, made known through the involuntary prophecies of their victims the coming of Germanus, with the result that one of the leading men in the country, Elafius by name, came hurrying to meet the holy men without having had any news of them through any regular messenger. He brought with him his son who had been crippled in early youth by a grievous malady. His sinews had withered and the tendons of the knee had contracted and his withered leg made it impossible for him to stand on his feet.
The whole province came along with Elafius. The bishops arrived and the crowds came upon them unexpectedly. At once blessings and the words of God were showered upon them. Germanus could see that the people as a whole had persevered in the faith in which he had left them and the bishops realized that the fallings-away had been the work only of a few. These were identified and formally condemned.
At this point Elafius approached to make obeisance to the bishops and presented to them his son, whose youth and helplessness made his need clear without words. Everyone felt acutely for him, the bishops most of all, and in their pity they had recourse to the mercy of God. The blessed Germanus at once made the boy sit down, then felt the bent knee and ran his healing hand over all the diseased parts. Health speedily followed the life-giving touch. What was withered became supple, the sinews resumed their proper work, and, before the eyes of all, the son got back a sound body and the father got back a son.
When I read the description carefully of Elafius's son's lameness, I happened to think of the following words (from Lewis and Short's Latin dictionary):
arto (not arcto ), āvi, ātum, 1, v. a. 1. artus,
I.to draw or press close together, to compress, contract (not found in Cic.).
I. A.. Lit.: omnia conciliatu artari possunt, * Lucr. 1, 576: “libros,” Mart. 1, 3, 3; Col. 12, 44, 2: “vitis contineri debet vimine, non artari,” Plin. 17, 23, 35, § 209: “angustias eas artantibusinsulis parvis, quae etc.,” id. 3, 6, 13, § 83.—
B. Trop., to contract, straiten, limit, curtail: “fortuna humana fingit artatque ut lubet, i. e. in angustias redigit,” Plaut. Capt. 2, 2, 54 Lind.; Liv. 45, 56: “tempus,” to limit, circumscribe, Dig. 42, 1, 2; 38, 9, 1: “se,” to limit one's self, to retrench, ib. 1, 11, 2 al. —
II. In gen., to finish, conclude, Petr. 85, 4.—Hence, artātus , a, um, P. a., contracted into a small compass; hence, narrow, close; and of time, short: “pontus,” Luc. 5, 234: “tempus,” Vell. 1, 16.
artus , ūs, m. id., mostly plur. (artua, n., Plaut. Men. 5, 2, 102; quoted in Non. p. 191, 12.—Hence, dat. acc. to Vel. Long. p. 2229 P. and Ter. Scaur. p. 2260 P. artibus; yet the ancient grammarians give their decision in favor of artubus, which form is also supported by the best MSS.; cf. arcus.—The singular is found only in Luc. 6, 754; Val. Fl. 4, 310, and Prisc. p. 1219 P.).
I. A.. Lit., a joint: “molles commissurae et artus (digitorum),” Cic. N. D. 2, 60, 150: “suffraginum artus,” Plin. 11, 45, 101, § 248: “elapsi in pravum artus,” Tac. H. 4, 81: “dolorartuum,” gout, Cic. Brut. 60, 217.—Sometimes connected with membra, Plaut. Men. 5, 2, 102: “copia materiaï Cogitur interdum flecti per membra, per artus,” in every joint and limb,Lucr. 2, 282; 3, 703 al.; Suet. Calig. 28; cf. “Baumg.-Crus., Clavis ad Suet.: cernere lacerosartus, truncata membra,” Plin. Pan. 52, 5.—
B. Trop., the muscular strength in the joints; hence, in gen., strength, power: Ἐπιχαρμεῖον illud teneto; “nervos atque artus esse sapientiae, non temere credere,” Q. Cic. Petit. Cons. 10.—More freq.,
II. The limbs in gen. (very freq., esp. in the poets; in Lucr. about sixty times): cum tremulis anus attulit artubus lumen, Enn. ap. Cic. Div. 1, 20, 40 (Ann. v. 36 Vahl.); so Lucr. 3, 7; cf. id. 3, 488; 6, 1189: “artubus omnibus contremiscam,” Cic. de Or. 1, 26, 121: dum nati (sc. Absyrti) dissupatos artus captaret parens, vet. poet. ap. Cic. N. D. 3, 26, 67: “copia concita per artusOmnīs,” Lucr. 2, 267: “moribundi artus,” id. 3, 129 al.: “rogumque parari Vidit et arsurossupremis ignibus artus, etc.,” Ov. M. 2, 620 al.: “salsusque per artus Sudor iit,” Verg. A. 2, 173; 1, 173 al.: “veste strictā et singulos artus exprimente,” and showing each limb, Tac. G. 17: “artusin frusta concident,” Vulg. Lev. 1, 6; 8, 20; “ib. Job, 16, 8.—Of plants: stat per se vitis sine ullopedamento, artus suos in se colligens,” its tendrils, Plin. 14, 1, 3, § 13, where Jahn reads arcus.
artus (not arctus ), a, um, adj. v. arma, prop.
I. Lit., close, strait, narrow, confined, short, brief: “exierunt regionibus artis,” Lucr. 6, 120: “claustra,” id. 1, 70; so id. 3, 808: “nec tamen haec ita sunt arta et astricta, ut ea laxarenequeamus,” Cic. Or. 65, 220: “artioribus apud populum Romanum laqueis tenebitur,” Cic. Verr. 2, 1, 5: “nullum vinculum ad astringendam fidem jure jurando majores artius essevoluerunt,” id. Off. 3, 31, 111: “compages,” Verg. A. 1, 293: “nexus,” Ov. M. 6, 242: “artostipata theatro,” pressed together in a contracted theatre, Hor. Ep. 2, 1, 60: “toga,” a narrow toga without folds, id. ib. 1, 18, 30 (cf. exigua toga, id. ib. 1, 19, 13): “nimis arta convivia,” i. e. with too many guests, who are therefore compelled to sit close together, id. ib. 1, 5, 29 et saep.—Hence, subst.: artum , i, n., a narrow place or passage: “ventus cum confercit, franguntur in artomontes nimborum,” Lucr. 6, 158 Lachm.: “multiplicatis in arto ordinibus,” Liv. 2, 50; so id. 34, 15: “nec desilies imitator in artum,” nor, by imitating, leap into a close place, Hor. A. P. 134.—
II. Trop., strict, severe, scanty, brief, small: “sponte suā cecidit sub leges artaque jura,” subjected himself to the severity of the laws, Lucr. 5, 1147: “Additae leges artae et ideo superbae quasqueetc.,” Plin. 16, 4, 5, § 12: “vincula amoris artissima,” Cic. Att. 6, 2: artior somnus, a sounder or deeper sleep, id. Rep. 6, 10: “arti commeatus,” Liv. 2, 34; Tac. H. 4, 26; cf.: “in artocommeatus,” id. ib. 3, 13: “artissimae tenebrae,” very thick darkness, Suet. Ner. 46 (for which, in class. Lat., densus, v. Bremi ad h. l., and cf. densus) al.—So, colligere in artum, to compress, abridge: “quae (volumina) a me collecta in artum,” Plin. 8, 16, 17, § 44.—Of hope, small, scanty: “spes artior aquae manantis,” Col. 1, 5, 2: ne spem sibi ponat in arto, diminish hope, expectation, Ov. M. 9, 683: “quia plus quam unum ex patriciis creari non licebat, artior petitioquattuor petentibus erat,” i. e. was harder, had less ground of hope, Liv. 39, 32; and of circumstances in life, etc., straitened, distressing, wretched, needy, indigent (so in and after the Aug. per. for the class. angustus): “rebus in artis,” Ov. P. 3, 2, 25: “artas res nuntiaret,” Tac. H. 3, 69: “tam artis afflictisque rebus,” Flor. 2, 6, 31; so Sil. 7, 310: “fortuna artior expensis,” Stat. S. 5, 3, 117: “ne in arto res esset,” Liv. 26, 17.—Adv.: artē (not arcte ), closely, close, fast, firmly.
I. Lit.: “arte (manus) conliga,” Plaut. Ep. 5, 2, 29: “boves arte ad stipites religare,” Col. 6, 2, 5: “arte continere aliquid,” Caes. B. G. 7, 23: “aciem arte statuere,” Sall. J. 52, 6: “arte accubare,”Plaut. Stich. 4, 2, 39.—Comp.: “calorem artius continere,” Cic. N. D. 2, 9, 25: “artiusastringi,” Hor. Epod. 15, 5: “signa artius conlocare,” Sall. C. 59, 2: “artius ire,” Curt. 4, 13, 34: “artius pressiusque conflictari,” Gell. 10, 6.—Sup.: “milites quam artissime ire jubet,” Sall. J. 68, 4: “artissime plantas serere,” Plin. 12, 3, 7, § 16.—
II. Trop.: “arte contenteque aliquem habere,” Plaut. As. 1, 1, 63; id. Merc. prol. 64: “arte etgraviter dormire,” soundly, Cic. Div. 1, 28, 59: “arte appellare aliquem,” briefly, by shortening his name, Ov. P. 4, 12, 10: “artius adstringere rationem,” Cic. Fat. 14, 32: “abstinentiamartissime constringere,” Val. Max. 2, 2, 8.—
III. Transf.: “arte diligere aliquem,” strongly, deeply, Plin. Ep. 6, 8; so also id. ib. 2, 13.
arthrītis , ĭdis, f., = ἀρθρῖτις,
I.a lameness in the joints, gout (in pure Lat., articularis morbus), Vitr. 1, 6.
The reader will note that these words contain among their meanings "joint", "contract", "lameness" and the like. The lameness of the boy was due in part to the contraction of the tendons of the knee joint.
Could it be that the author of the vita had not derived his story of lameness from the eponym Gewis, but from the name Arthur? Either Arthur or Artorius could well have been etymologized by drawing on Latin words like artus and arto. In this way Arthur was thought to mean a boy whose knee joint had suffered contraction of the tendons.
Needless to say, this would also mean that Cerdic son of Elafius/Elesa was quite possibly Arthur!
Now, if so, this does bring into question whether Ceredig of Wales was really the son of Cunedda (= Ceawlin of the ASC). I've already discussed the possibility that some of the sons of Cunedda were actually the sons of other chieftains, but that they were associated with the famous founder of Gwynedd at a later time. We might even postulate that these "sons" were actually members of Cunedda's teulu. This word meant not only war-band or retinue, but also "family."
Here are the definitions for teulu from the GPC:
a Rhieni a’u plant fel uned, pobl sy’n perthyn i’w gilydd drwy waed, priodas, mabwysiad, &c., tylwyth, plant rhywun; llwyth, cenedl; grŵp o bobl sy’n byw gyda’i gilydd mewn un tŷ, tyaid; grŵp o bobl a unir gan glymau cymdeithasol, crefyddol, gwleidyddol, &c., unrhyw grŵp o bethau, organebau, &c. sy’n perthyn i’w gilydd (hefyd fel dosbarthiad tacsonomig rhwng urdd a thylwyth):
(nuclear or extended) family; tribe, nation; household; family (related group of persons, things, organisms, &c., also as taxonomic classification).
b Dilynwyr, gweision, neu gymdeithion brenin, &c., gosgordd, gwarchodlu, llu rhyfel; llu, torf, pobl:
royal, &c., retinue, retainers, or entourage, comitatus, bodyguard, household troops, war-band; host, crowd, people.
Ceredig, therefore, may have been one of Cunedda's retainers, but not actually his son.
Much of this depends, of course, on Elafius/Elesa being Ceredig's/Cerdic's father. Kenneth Sisam could be right (his case, supported by David Dumville, is very strong), and Elesa could merely be a derivative of Aloc/Alusa of the Bernician pedigree. My attempt to find a Celtic prototype for Elesa/Esla would be in vain. But if that is true, then the very early St. Germanus story would have to be dependent on the Anglo-Saxon genealogy that grafted Aloc/Alusa onto the Gewessei line of descent.