King Edwin’s Sister’s Son

Thinking more about Willibrord’s devotion to St. Oswald and Oswald’s placement on Willibrord’s calendar with its Deira-centric focus, recalls the stress Bede places on Oswald’s kinship with King Edwin of Deira.

“By the efforts of this king the kingdoms of Deira and Bernicia, which had up to this time had been at strife with one another, were peacefully united and became one people. Now Oswald was the nephew of Edwin through his sister Acha, and it was fitting that so great a predecessor should have so worthy a kinsman to inherit both his religion and his kingdom.” (Bede, History, III:6; McClure and Collins, 1994:119)

This is one of the few times in the History that Bede bothers to mention the mother of a king. We are usually left to assume (and today argue/discuss) about the mothers of kings. It is worth noting that Bede never actually states that Oswald is the son of Æthelfrith; he says he is the brother of Eanfrith, Æthelfrith’s oldest son.

I think it is significant that Bede claims that Oswald was the first to unite the two kingdoms and became one people, considering he has narrated how Æthelfrith and Edwin each controlled the opposite kingdom. Bede is claiming Oswald was the person who created Northumbria, in effect ethnogensis for Northumbria begins with Oswald (as discussed here).

Succession of the Sister’s Son is known elsewhere among the peoples of the British Isles. According to Bede, this was the primary method of succession among the Picts, although this still generates a great deal of academic discussion.

“As the Picts had no wives, they asked the Scots for some; the latter consented to give them women only on the condition that, in all cases of doubt, they should elect their kings from the female royal line rather than the male; and it is well known that the custom has been observed among the Picts to this day.” (Bede, I.1, McClure and Collins, 1994: 11).

Alex Woolf argues that this only happened under special circumstances and those circumstances happened to occur during Bede’s maturity (Clancy 2004, Woolf 1998). Woolf’s paper is probably the widest ranging discussion on historic succession in the last generation that I know of. He points out other successions bolstered by claims to the female line including the foundation of the second dynasty of Gwynedd by Merfyn of Man (c. 825-844). Interestingly, Woolf (1998:151-152) noted that King Cenwulf of Mercia claimed to be descended from a third brother of Penda named Cenwealh but probably was descended from Penda’s sister (who had been cast out by Cenwealh of Wessex). Thus, the children of Penda’s sister must have continued to have status in Mercia generations after the deaths of her brothers Penda and Eowa. In effect, Cenwulf of Wessex may have been a sister’s son succession several generations removed. Woolf notes that these successions, including Nechtan mac Der-Ilei, King of Picts whom Abbot Coelfrith corresponds, had to be supported by some fiction. (In Nechtan’s case that was an Irish influenced foundation legend.) Ironically, Woolf seems to have overlooked Oswald’s succession in Deira as a sister’s son or a form of matriliny.

Another possible example is the succession of Cadafael ap Cynfeddw to Gwynedd after Cadwallon’s death at the battle of Denisesburna. According to the Welsh triads, Cadafael was one of three kings whose father was a villein (low born, non-royal). He comes out of nowhere, I think I have read somewhere, don’t remember where, that he may have been a sister’s son of Cadwallon or related somehow through the female line. Alternatively, he could have been one of Cadwallon’s warlords. Cadafael is best known as being part of Penda’s army that besieges Oswiu, probably at Stirling. He pulls his army out of Penda’s Grand Army before Oswiu ambushes them at Winwæd and therefore survives the fall of Penda. For this his people nicknamed him Catabail Catguommed (Battle-Taking, Battle-Refusing), so its a pun on his name Cadafael/Catabail (Bartrum p. 72). Anyway, Cadafael seems to be a placeholder until Cadwallon’s son Cadwalader is old enough to succeed. For Gwynedd (North Wales), Cadwallon’s death and the loss of nearly all the army so far from home would have been about as traumatic for Gwynedd as the deaths of Edwin and Osric had been for Deira.

Woolf’s analysis of Anglo-Saxon royal successions (Kent, Berncia/Northumbria, Mercia and Wessex) showed that overall sons succeeded royal fathers only 1.44: 1 vs. non-royal fathers and intruders. Non-royal fathers could still be from the royal patrilineage, but had not held the throne themselves. Kent and Northumbria were more stable [Kent 2:1, Northumbria 1.86:1], but Mercia was much more unstable [1:1.16]. Woolf’s whole point is that Pictish succession doesn’t look much less patrilinear than Mercia, Wessex or Connacht and Munster, except that the Pictish list lacks the clusters of father to son succession seen in the successful Anglo-Saxon dynasties (such as the Æthelfrithings). There is not one father-to-son transmission of the throne before the late 8th century (Woolf, p. 154-158). Although Woolf sets out to prove that Pictish succession fits a patrilinear pattern, he also shows us how often the traditional patrilinear succession failed. Some of these kings have known female links to the royal lineage and some of the intruders may have as well.

If we turn to the church, many abbots and bishops are succeeded by their sister’s sons from Wilfrid’s sister’s son Beornwine who managed his estates on the Isle of Wight to Bishop Leuthere, nephew of Bishop Agilbert (although I can’t be sure he was a sister’s son). Plenty of abbots are kinsmen of a previous abbot, such as Eosterwine of Wearmouth and Tatberht of Ripon.

The sister’s son is a common motif in insular literature. Succession of the sister’s son is well known in the Old English poem Beowulf, where Beowulf succeeds Higelac as a sister’s son and it is implied that his successor will be Wiglaf, his sister’s son. The sister’s son motif comes up in the story within a story in Beowulf, as it is part of the Fight at Finnsburg story told in Beowulf. I’m sure this has been talked about in Beowulf circles for ages, and no doubt with the recent movie not one angle of Beowulf will be left unexamined. Sigh…I prefer heroes who pull swords from stones and there are sister’s sons a plenty there too! Gawain and his brothers are Arthur’s sister’s sons and Modred is the ultimate sister’s son — son of the king and his sister! It goes on, Tristan is the sister’s son of King Mark and I know there are sister’s sons in Irish literature.

Sister’s sons (and other female links) seem to have successfully succeeded in times of crisis. Oswald’s succession was certainly such a period of crisis. Deira’s two previous kings had been slain in battle in less than a year. The possibility that Oswald was embraced within Deira as an acceptable king, a member of the Deiran royal family, who achieved vengeance for the deaths of their last two kings has implications for how the succession of Oswine and Oswald’s son Œthelwald are viewed. The acceptance of Oswald as a member of the Deiran dynasty also may indicate how Ecgfrith son of Eanflæd son of Edwin eventually united the two kingdoms for the last and final time in 679. We really shouldn’t be surprised that such humane decisions were made even though they are not provided for in any law of succession that I know of. In an era where there are so many intruders seizing kingdoms, surely sister’s sons are preferable to an intruder.

For all his efforts to claim Deira, King Oswiu never quite managed it. I don’t believe that he and Oswald shared the same mother, so that Oswiu had no claim in Deira. Oswiu was buried in the Church at Whitby where, soon after his death, the remains of King Edwin were transported and became the royal focus, upstaged in his greatest monastery. His teenage son Ælfwine was made King of Deira indicating that it was not yet possible for Ecgfrith to unite them under his rule. They were united under Ecgfrith only when there were no other possibilities for an independent king of Deira with a connection to the Deiran royal family existed. Had Ecgfrith failed to unite Deira and Bernicia into Northumbria, his successor Aldfrith may not have been able to hold the kingdom at all. Under Kings Oswine and Œthelwald Deira had already shown sympathy with Merica, so it was imperative for Ecgfrith to unite the kingdoms before the Deiran bloodline was exhausted.

Bede’s claims that Oswald united the people of Bernicia and Deira into a single people may be a gilding of history. By c. 731, Northumbria had been united long enough for a more romantic version of history to develop. It is possible that Oswald showed the people that peaceful unity under a mutually acceptable king was a real goal for both kingdoms. After that unity was achieved again under King Ecgfrith with no apparently viable Deiran claimants left, unification of Northumbria became an accepted reality.


Bede, Ecclesiastical History of the English People. J. McClure and R. Collins, eds (1994). Oxford Classics.

Alex Woolf (1998) “Pictish matriliny reconsidered’ The Innes Review 2:147-167.

Thomas Owen Clancy (2004) “Philosopher-King: Nechtan mac Der-Illei” The Scottish Historical Review 83(4):125-149.

Peter C Bartrum. (1993) A Welsh Classical Dictionary: People in History and Legend up to about AD 1000. National Library of Wales.


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