Saxon Kings
Cerdic: length of reign
Cynric
Ceawlin
Ceol
Ceolwulf
Cynegils
Cenwahl
Sexburg (a queen)
Aescwine
Saxon Kings
Cerdic: length of reign
Cynric
Ceawlin
Ceol
Ceolwulf
Cynegils
Cenwahl
Sexburg (a queen)
Aescwine
Genealogical Preface
500 + 16 = 516 [16-year reign]
516 + 27 = 533 [17-year reign]
[543 +31] = 574 [31-year reign]
574 + 6 = 580 [ 6-year reign]
580 + 17 = 597 [17-year reign]
597 + 31 = 628 [31-year reign]
628 + 31 = 659 [31-year reign]
659 + 1 = 670 [ 1-year reign]
660 + 2 = 662 [ 2-year reign]
Anglo-Saxon Chronicle
519 to 534 = 15 years
534 to 560 = 26 years
560 to 591 = 31 years
591 to 597 = 6 years
597 to 611 = 6 years
611 to 643 = 32 years
643 to 672 = 29 years
672 to 673 = 1 year
674 to 676 = 2 years
Using Ceawlin as an example, the Genealogical Preface shows that his reign began in 543, whereas the Chronicle indicates that his reign began in 560. And similarly, according the the Preface, his reign ended in 574, while the Chronicle reports that his reign ended in 591. It was this discrepancy which Charles Plummer indicated was "impossible to reconcile."
And yet, after a great deal of deliberation and research, I reconciled the discrepancies between the two manuscripts according to the following table.
Cerdic
Creoda
Cynric
Ceawlin
Ceol
Ceowulf
Cynegils
Cenwahl
Sexburg
Aescwine
Genealogical Preface
500 + 16 = 516
517 + 17 = 534
534 = 36 = 560
560 + 25 = 585
585 + 6 = 591
591 + 17 = 608
608 + 31 = 639
639 + 31 = 670
670 + 1 = 671
671 + 2 = 673
Anglo-Saxon Chronicle
34 years: 500 - 534
[Left out of the ASC genealogy]
26 years: 534 - 560
31 years: 560 - 591
[Combined in ASC with Ceawlin’s reign]
14 years: 597 - 611
31 years: 611 - 642
29 years: 643 - 670 [MSS A, B, C and E]
1 year: 670 - 671
2 years: 673 - 675
Amazingly, in my table of reconciliation, you can note that there is not more than a two-year discrepancy in the reigns of the Kings of the West-Saxon House, whereby if you look at the example of Ceawlin's reign there was originally a 17-year discrepancy. There turns out to be, therefore, remarkable accuracy in the recordings between the Genealogical Preface and The Anglo-Saxon Chronicle, showing, in my opinion, indisputable evidence of the accuracy and reliability in the chronology of the two documents.
Because of the cruciality of this revelation, I expect proper citation for any quotation of the above information. If you want the details of the process of this reconciliation, please refer to The Historic King Arthur, which is, of course, copyrighted, as is the information conveyed above.