Gewis

According to the Old English Dictionary:

Giwis, es;

Gewis

m. Gewis, the great grandfather of Cerdic :-- Se Cerdic wæs Elesing, Elesa Esling, Esla Gewising, Gewis Wiging Cerdic was the son of Elesa, Elesa the son of Esla, Elsa the son of Gewis, Gewis the son of Wig, Chr. 495; Erl. 2, 5: 597; Erl. 20, 7. Giwis, 552; Erl. 16, 19. According to Asset it was from this name that the term Gevissæ, applied by Bede to the West Saxons, was derived. 'Gewis, a quo Britone totam illam gentem Gegwis nominant,' see Grmm. Gesch. D. S. 458. For the use by Bede, see Bd. 3, 7-'Gens Occidentalium Saxonum qui antiquitus Gevissæ vocabantur ... primum Gevissorum gentem ingrediens,' where the translation has 'West Seaxna þeód ... Ðá com he ǽrest upp on West Seaxum.' See also 4, 15, 16. Smith's note on the word is 'Gevissæ. Saxonicum est pro Occidentalium. Sic Visigothi præposita tantum Saxonica expletiva Ge.' See Thorpe's Lappenberg i. 109, note. ge-wis,gewis