It was the excessive fecundity of Edward III (1312-1377) that, ironically, started it all. Edward had the following children by his wife Phillippa of Hinault: (1) Edward the black prince, (2) Isabella, Lady of Coucy, (3) Joan of England, (4) William of Hatfield, (5) Lionel of Antwerp , First Duke of Clarence, (6) John of Gaunt, First Duke of Lancaster, (7) Edmund of Langley, First Duke of York, (8) Mary, Duchess of Brittany, (9) Margaret, Countess of Pembroke, (10) Thomas of Woodstock, First Duke of Gloucester, and finally (11-14) John, Jane, and Joan de Southeray. This set the stage for some monumental family squabbles concerning who got the prize after Edward shuffled off his mortal coil.
Then there was the Hundred Years War, which was a series of conflicts from 1337 to 1453 (more like the hundred and sixteen years war but never mind). In 1066 William the Conqueror added England to his existing domain in Normandy. At the same time he was the vassal to the king of France. This conflict or series of conflicts was the protracted sorting out of the national identities of France and England. For a long time English kings had claim to a lot of French real estate owing to the complex web of intermarriage and primogeniture.
Primogeniture of course is the practice of maintaining royal and ducal houses and land by the expedient of granting the eldest son of the household ownership of all. The younger siblings in this arrangement were left with nothing. This was thought preferable to the division of kingdoms into however many heirs as there were, which, in time would lead to a fragmentation of kingdoms and an intolerable situation related vividly in Shakespeare's King Lear.
Getting back to Henry the Eighth, these successional problems seemed to have been the focus of much of his reign. It has been speculated that Henry may have been a victim of McLeod Syndrome, which leads to both neurological problems in the possessor but in hemolytic disease in his children (1). It works in much the same way as Rh disease in which an Rh- mother develops antibodies to her Rh+ child. The first pregnancy goes without a hitch because the mother gets immunized by exposure to the baby's blood at the time of birth. However each successive child dies from an immune assault on its blood via antibodies that cross the placenta.
If only I could have sat down with King Henry and explained this to him without being labelled a heretic and burned at the stake. And if I could also have explained to him the fact that the father (you, Henry) are the determiner of the sex of the child and that it has very little to do with the woman. In short the problem was with HIM not with the ladies he was mating with.
I would say to him:
"In the process of meiosis, wherin males have an X and a Y chromosome in each of their cells, one of the 23 pairs of chromosomes all normal humans have.
The production of gametes (sperm and egg) requires the reduction of those chromosomes to half their number (23 individual chromosomes) that then go on to unite with the 23 chromosomes of the mother. Since each one of your sperm cells contains either an X or a Y you determine the sex of the child. If an X sperm cell reaches the egg first, then it combines with one of the mother's X chromosomes (She has two X chromosomes) then the child is a girl. :( If one of your Y sperm cells reached the egg first then the child is a boy. :) And your succession is assured.
"The fact is, Hank, (can I call you Hank?) every child is a crapshoot. You KNOW that the child gets half of everything you inherited from your parents, but what you don't know is which half. I am talking only about your "genes" not your royal possessions. The only way to avoid this problem is if I could take a sample of your precious jizz back to the 21st century and put it in an ultracentrifuge.
You see, your X chromosome bearing sperm cells are heavier than the Y chromosome bearing ones, enough so that if you speed up the process of gravity (using this machine) the heavier ones you don't want will sink lower in the test tube. Then we could harvest the Y chromosome ones you want from the top of the density gradient and deliver them to the queen's womb at the right moment in her 28 day cycle and you would have a male heir or at least we'd hope so. Even in the 21st century this isn't an exact science. You would have to promise to keep your hands off her until she has conceived.
"But of course you have to do this when the queen is ovulating. Some time between the time of her previous period and the next one she will ovulate, and you can kind of tell when this is, by using this handy digital thermometer.
Just so I don't try to switch tubes or something let me take Cromwell back to verify the procedure. Less than an hour later I'll return and we'll artificially inseminate your queen. Now just to help you in producing your sample material I have taken the liberty of bringing along these magazines. I expect you will find something to your liking here, but I'll need those back when you are done, okay?"
As it happened of course, it was a successional train wreck. "Why can't you accept it, Henry, one boy and two girls isn't bad. Shame about all those miscarriages however, and in any case, none of your children will make a grandparent of you: your male heir Edward VI, will die when he is only 15, Mary won't be able to conceive at all, and Elizabeth, seeing what a mess marriage and reproduction had been for you and the gruesome fact that you blithely chose to ax her mum, will decide not to marry at all. Can you blame her?
"So after the last of your heirs die the English will have to bring in this bisexual king from Scotland to carry things on for you royals after 1603. Even James the first will have better luck in the baby daddy game than you did, and he liked boys. But then England will get Scotland in the bargain so I guess that should be consolation enough, but France will never be your dominion, and besides, around the middle of the next century the people started to get really tired of being jerked around by their kings and queens and also got tired of being dictated to regarding how they were
And besides, I suspect a major problem you and all your other royal kindred had was this matter of inbreeding. If you are going to be marrying your first and second cousins like a bunch of demented hillbillies, you shouldn't have been surprised, knowing what we know now, that you got miscarriages and mental defectives and other problems. Ask the Habsburgs about it. They had it even worse.
And if you must view it from a theological point of view then it is self-evident that God hates inbreeding. Don't do it, or God will punish you. Nuff said?