In another article, I argued for 605 AD as a likely date for the annexation of Deira by Aethelferth of Bernicia, based on evidence from Historia Brittonum (HB) and consistent with Bede and the medieval chronicler Reginald of Durham. The usual interpretation of the entries in the Anglo-Saxon Chronicle (ASC) appears to suggest that Deira was annexed by Aethelferth's father Aethelric in 588 AD. How might this apparent conflict be resolved?
A.D. 560. This year Ceawlin undertook the government of the West-Saxons;
and Ella, on the death of Ida, that of the
Northumbrians; each of whom reigned thirty winters.
A.D. 588. This year died King Ella; and Ethelric reigned after him five years.
A.D. 593. This year Ethelfrith succeeded to the kingdom of the Northumbrians.
He was the son of Ethelric; Ethelric of Ida.
A.D. 617. This year was Ethelfrith, king of the Northumbrians, slain by Redwald,
king of the East-Angles; and Edwin, the son of
Ella, having succeeded to the kingdom, subdued all Britain
In the year 547, Ida began his reign, which lasted for 12 years.
He [Pope Gregory] sent to Britain Augustine, Mellitus and John, and many others, with God-fearing monks with them, to convert the English to Christ. [ .] However, the people of the Angles north of the river Humber, under Kings Aelle and Aethelfrith, did not at this time hear the Word of life.
--Bede, On the Reckoning of Time, Chapter 66 (4557). Translated by Faith Wallis.
GENEALOGY OF THE KINGS OF BERNICIA.
57. Ida had twelve sons, Adda, Belric Theodric, Thelric, Theodhere, Osmer,
and one queen Bearnoch, Ealric. Ethelric begat Ethelfrid: the same is AEdlfred
Flesaur.
Ida, the son of Eoppa, possessed countries on the left-hand side of Britain,
i.e. of the Humbrian sea, and reigned twelve years.
63. Adda, son of Ida, reigned eight years; Ethelric, son of Adda, reigned
four years. Theodoric, son of Ida, reigned seven years. Freothwulf reigned
six years. In whose time the kingdom of Kent, by the mission of Gregory, received
baptism. Hussa reigned seven years.
THE KINGS OF THE DEIRI
61. Woden begat Beldeg, Brond begat Siggar, who begat Sibald, who begat Zegulf,
who begat Soemil, who first separated Deur from Berneich (Deira from Bernicia.)
Soemil begat Sguerthing, who begat Giulglis, who begat Ulfrea, who begat Iffi,
who begat Ulli, Edwin, Osfrid, and Eanfrid. There were two sons of Edwin,
who fell with him in battle at Meicen, and the kingdom was never renewed in
his family, because not one of his race escaped from that war;
On the face of it, this looks as though one source must be wrong. However, it seems to me they are not wholly incompatible, and the clue to a possible reconciliation is in point 5 above. The ASC was written in the reign of Alfred the Great in the late ninth century, three centuries distant from events at the turn of the sixth/seventh century. When the ASC was compiled, the old kingdom of Northumbria was under Danish rule and both its rival dynasties were extinct. Any records of the lost kingdom available to the ASC compilers in Wessex were probably scanty at best, and as the AD dating system was popularised by Bede in the 8th century, it's unlikely that any such records contained AD dates. The ASC compilers probably had little more than king lists and/or genealogies, from which they may have back-calculated dates as best they could by adding up reign lengths. If they did not realise there had been two rival lines of kings in sixth/seventh century Northumbria, and/or if the records they had were incomplete, it would have been very difficult indeed to arrive at a coherent set of dates. Small blame to the chroniclers if they decided not to waste too much time trying to reconstruct precise details of two extinct dynasties in a defunct kingdom three centuries earlier.
The ASC entry for 588 says that Aelle was succeeded by Aethelric, who reigned 5 years. If you assume that this Aethelric was also Aethelric father of Aethelferth of Bernicia, and back-calculate the dates from the date of Aethelferth's accession (593) that can be inferred from Bede, you get more or less the dates given in the ASC, with the attendant problems outlined above.
If, however, the Aethelric who succeeded Aelle was not the same man as Aethelric father of Aethelferth of Bernicia, the situation becomes much simpler. This Aethelric could have succeeded Aelle as king of Deira at any time after after 597 AD, when Augustine arrived in Britain and Bede says that Aelle and Aethelferth were kings north of the Humber. It doesn't imply that Bernicia took political control of Deira at the time, so it doesn't conflict with HB's evidence that Aethelferth took over Deira in 605, 12 years into his reign.
If there were two Aethelrics, there is no reason why Aethelric of Bernicia should not have ruled for 4 years (HB) and Aethelric of Deira for 5 years (ASC), so that problem also disappears.
If Aelle and Aethelric of Deira ruled in parallel with a separate line of kings ruling in Bernicia, we can accommodate the missing kings from HB. There are two fixed points in the Bernician succession; Ida beginning his reign in 547 and reigning for 12 years (taking us to around 559), and Aethelferth beginning his 24-year reign in 593. Both these dates are attested by Bede. There is a gap of 34 years between the end of Ida's reign and the beginning of Aethelferth's. The five kings of Bernicia listed in HB are as follows: Adda son of Ida 8 years; Aethelric son of Adda 4 years; Theodoric son of Ida 7 years; Freothwulf 6 years; Hussa 7 years. Between them they add up to 32 years, so they all fit into the gap between Ida and Aethelferth. The two-year discrepancy might indicate a missing short-lived king, or it may just be a rounding error. In either case, it is much less of a problem than four missing kings.
So, if Aethelric of Deira existed and ruled Deira for 5 years after Aelle, who was he? There are several possibilities:
All of these are possible, and there is no firm evidence for or against any of them, so you can take your choice.
The most obvious place for Aethelric's five-year reign is 600-605, which would mean he, not Aelle, would have been the king of Deira displaced by Aethelferth in 605. The only evidence against this is Reginald of Durham, whose chronicle says that Aethelferth killed and deposed Aelle to take over Deira. This isn't very strong evidence, as Reginald was writing in the twelfth century and any sources had had 500 years to become garbled by then. However, Reginald's statement can be accommodated if Aethelric was a client-king or under-king installed after Aelle's death to run Deira under Aethelferth's overall control. It was not unknown for under-kings to govern part of a kingdom, as Bede mentions an under-king of Deira during Oswy's reign in 651 (Book III, Ch. 14). Client-kings have tremendous potential to confuse records if one chronicler counts the client as a proper king and another doesn't.
When writing fiction, you have to choose one of the possibilities and go with it. In Paths of Exile I decided to make Aethelric of Deira a nephew of Aelle (because I wanted Hereric's father for another role in the story), and to make him a client-king installed in 605 under Aethelferth's control (because that would account for confusion in the records, and because I liked the idea). I don't claim that this is the Right Answer by any means, but as set out here I think it is a plausible one.
Full-text sources available online are linked in the text
Bede: The Reckoning of Time. Translated by Faith Wallis. Liverpool University Press, 1999, ISBN 0-85323-693-3.
*My thanks to Doug Tankard for drawing my attention to the reference to Aelle
and Aethelferth in The Reckoning of Time.