A genealogical mystery deepens (originally published in the December 2013 Bulletin)

The suggestion in John Ashdown-Hill’s Royal Marriage Secrets (pp.69-74) that Edmund “Tudor” may have been fathered by Edmund Beaufort, of Somerset, and not by Owen Tudor, Catherine de Valois’ servant and apparent illegal husband, is most intriguing. It is clear that Edmund was a “transitional child” between one of her relationships much commented on at the time and one better documented afterwards. Is Edmund unique in this? The further hypothesis that I detail here would involve yet another possible surname for the 1485-1603 monarchs, although it has less evidence to date than the impressive array already assembled in the Beaufort-Tudor case so far.

Traditional sources record that Catherine de Roet (c.1350-1403), after her husband Sir Hugh Swynford died, became the mistress of John of Gaunt (1340-99) and bore him four children. They were legitimated from 1397 – the words “excepta dignitate regalis” being added a decade later – under the name Beaufort after his second wife (Constanza of Castile) died in 1394 and he married Catherine de Roet. Those children were:
John, Marquess of Dorset and Somerset (c.1371-1410)
Henry, Cardinal Beaufort (c.1375-1447).
Thomas (c.1377-1428).
Joan (c.1379-1440), who married Ralph Neville to become Countess of Westmorland and ancestress of almost all monarchs from 1461.
These dates have all been taken from the relevant ODNB articles. The births are all thought to have occurred during the 1370s. Note that the middle and younger sons were both childless, Henry having taken holy orders and Thomas by chance, and that the fourth was female so that her children all taking her husband’s surname, thus Dorset was the progenitor of all future Beauforts, including Edmund of Somerset.

The ODNB article on Catherine is of the view that Sir Hugh died in November 1371, probably after Dorset’s birth. Some writers, including Ellis, take the view that Dorset was “in double advoutrow goten” (ie both partners were committing adultery), as quoted in Richard’s “Tydder” warrant to John Russell, his Chancellor. At the very least, we have another “transitional child”. The Complete Peerage entry gives Sir Hugh’s death year as 1372 and agrees that, contrary to Kingsford’s conclusion in the original DNB, Dorset was born by then because he was granted a hundred marks a year by Richard II in 1392.
However, English common law has the “presumption of paternity”, referred to by Blackstone in his 1769 opus Commentaries on the Laws of England, which states that any child born to a married woman is assumed to be that of her husband unless it can be proven otherwise. This principle must date from before it was applied as “Lord Mansfield’s Rule” in the following decade (Goodright ex dim. Stevens v Moss et al (1777) 2 Cowper 591, English Reports citation 98 ER 1257) and would presumably apply even if the husband dies before the child is born.
If this applied in the late fourteenth century, Dorset would legally be Sir Hugh Swynford’s son and it would not take much stretching of the imagination for this to be a biological relationship as well. The 1235 “Statute of Merton” stated that a child born before its parents’ marriage would be illegitimate, implying that the converse is also true – hence the presumption. At the same time it is easy to understand why a small child should be raised as the illegitimate child of a living royal Duke rather than the legitimate son of a dead knight.
The implications are also significant in that no Beaufort after the Cardinal’s death would have been of English royal descent. Furthermore, this corollary is capable of disproof through Richard’s rediscovery in that Dorset’s descendants the Dukes of Beaufort are his only Y-chromosome comparators since Viscount Lisle died in 1542 (or even Edward VI in 1553). However, a mismatch would not actually prove the point as there may have been an incorrectly identified father later on, or a degraded sample.

Sources:
ODNB “Katherine, duchess of Lancaster” by Simon Walker [http://www.oxforddnb.com/view/article/26858, accessed 22 Aug 2013].
ODNB “Beaufort, John, marquess of Dorset and marquess of Somerset” by G.L. Harriss [http://www.oxforddnb.com/view/article/1861, accessed August 22, 2013].
http://en.wikipedia.org/wiki/Paternity_(law) (accessed August 23, 2013).
http://en.wikipedia.org/wiki/William_Murray,_1st_Earl_of_Mansfield (accessed August 23, 2013).
http://uniset.ca/other/cs4/98ER1257.html (accessed August 26, 2013).
The Complete Peerage (vol. XIIi, pp. 39-40, 1953).

Acknowledgements:
Thanks to Ben Redsell (Ipswich) and Susan Troxell (Philadelphia).