The distinguished genealogist Sir Anthony Wagner, who lived into the 1990s, reckoned the number of traceable descendants of medieval English kings was in the millions. In the September 2000 issue of the Society of Genealogists magazine the new editor referred to an estimate that about three million in the UK and forty million in the USA could trace descent from Edward I and his queen. He did not cite a source for this estimate. And since Edward I had two queens and legitimate issue by both, this estimate doesn't take us very far. Then again, note the phrase 'can trace'. This one takes to mean 'have a pedigree already drawn up'. What of those who could trace but don't, perhaps because they are not interested? Or those who descend illegitimately? This book has built on recent work tracing the progeny of royal bastards to show that a huge percentage of royal descendants, perhaps a majority given Henry I's fecundity, originated on the wrong side of the blanket.

There are several variables one simply cannot quantify. The first two or three generations of royally-connected males could well have begotten many more bastards than are mentioned in the records, since historically such people had the leisure, wealth, and prestige to carry out multiple seductions. They also travelled more extensively than their social inferiors, so will have had more opportunity to spread their seed. Again, many of the remoter descendants usually married into aristocratic or gentry families, where similar advantages arose when trying to seduce village girls or one's neighbour's wife hence greater-than-usual fathering of children on the side. Finally, a significant percentage of such royally-descended aristocratic/gentry connections were with recusant families (Staffords, Stonors/Camoyses, Fitzalans) or Catholic royal houses on the continent (those of Castile and Portugal). Such people did not practice artificial contraception until recently (if then), hence have had unusually large families over the last few generations.

Until recently reference books on royalty swept birth the wrong side of the blanket under the carpet. God knows why. Though a hurdle when claiming a throne - but not too much of one, no Becher's Brook, or William the Bastard wouldn't have romped home in the Hastings Handicap - it shrinks to a wormcast where descent is concerned. The 'blood' under discussion, being metaphorical, is equally royal whether or not the veins it courses through belong to people whose parents were properly married. Besides, bastardy isn't just an accident of birth. It has sometimes been imposed retrospectively by Act of Parliament. Paradoxically, Richard III legislated Edward V into illegitimacy in 1483; so in 1534 did Henry VIII his daughter Mary then in 1536 his next daughter Elizabeth (as well as Mary all over again). Bastardy may also be imposed in advance, as happened through George Ill's Royal Marriages Act of 1772 with his son the Duke of Sussex's children not just before they were born but before even the Duke was.

Such measures can't taint blood royal. The FitzGeorge Balfours have no right to the throne, being irregularly descended from George III's youngest son Adolphus Frederick, but no one would deny that descent or that it is royal. And because William the Conqueror was a bastard, it has seemed only logical to include bastard descendants of sovereigns here.

Part 3 of 7.