Yr argraffiadau cyfochrog
Mewn papur yn Studia Celtica (12/13, 1977/8, Caerdydd), 'The Welsh Annals', ysgrifennodd Yr Athro Dumville, "(w)hat other work still remains to be done on all these texts? There is, in fact, a considerable amount of research still needed. The most pressing . . . is a study of their chronological structure . . . Much can be learned of sources and transmission from a rigorous investigation of the chronological structure, and a reasonably accurate dating can be deduced for the sequence of early Welsh history, which will replace the arbitrary or haphazard dates now holding sway.
Following the completion of the chronological investigations, the way will be clear for a new edition of the Latin texts. Plainly, much thought must be given to the arrangement of such an edition, but the best method would seem to be the presentation of parallel texts as follows (the dates are those at present in use; they will have to be modified in detail): (1) B and C, Creation to 444; (2) ABC, 445–977; (3) BC, 978–1189; (4) BCE, 1190–1253; (5) BCDE, 1254–66; (6) BCD, 1267–88." Mae'r Athro Dumville ei hun wedi llunio testun cyfochrog am y cyfnod ABC 684–954 (2002, Annales Cambriae, A.D. 682–954: Texts A–C in Parallel, Department of Anglo-Saxon, Norse and Celtic, Prifysgol Caergrawnt).
Roedd hyn yn achos o roi'r drol o flaen y ceffyl i ryw raddau. Dim ond nawr ar ôl i argraffiadau mwy dibynadwy o'r testunau sydd wedi goroesi gael eu pennu y mae'n bosibl creu argraffiadau cyfochrog yn unol â'r drefn a awgrymwyd. Mae'r rhain yn datgelu cronoleg Croniclau'r Byd a'r blwyddnodion, a'u problemau, ynghyd â'r berthynas rhwng y gwahanol destunau eu hunain, a rhwng y testunau a'u ffynonellau.