On New Year’s Day of 1511, queen Katherina of Aragon gave birth to the son everyone was waiting for. The newborn was named Henry after his father and he appears to have been a normal and healthy baby, prompting widespread and prolonged celebration. Henry and Katherina were thrilled with their new son, whom they hoped would be the first of many. Henry VIII went on a pilgrimage to a shrine dedicated to the Virgin Mary in order to give thanks for the birth of his heir, and the proud parents hosted a tournament at Westminster in mid-February to celebrate his arrival.
What does the birth of a healthy baby mean vis-à-vis the theory that Henry had Kell positive blood? It is completely compatible with the hypothesis, because the little boy would have been one of Katherina’s lucky Kell negative infants, and was therefore able to thrive during gestation. If anything, it strengthens the theory. Of Katherina’s known pregnancies only five would reasonably be expected to be at risk for alloimmunization in the womb. There are circumstances wherein the first baby, her stillborn girl, would have possible been exposed to Katherina’s antigens but it is certain (provided the theory is correct) that the queen’s last five pregnancies would have been at risk of alloimmunization. If the New Year’s Prince was Kell negative, then the ratio of Kell+ or Kell- infants born to Katherina looks more balanced; of the five pregnancies, 3 would have been Kell positive and 2 would have been Kell negative.
Sadly, the newborn Henry died on February 22. No one knows why for sure. Unfortunately, there were a seemingly endless number of reasons a baby could die in infancy during the sixteenth century so there is no way of knowing what killed the small heir.
There is a slight possibility that Kell positive alloimmunization may have killed the New Year’s Prince. If the infant had a Kell positive blood type then his death might have been from hyporegenerative anemia, which is a delayed form of hemolytic disease of the newborn. However, there are no historical records that hint at symptoms of delayed HDN in baby Henry; only the timing of his death makes it even remotely feasible.
What is know for sure is that his loss caused his parents profound grief. If the baby had lived to remain Henry VIII’s heir, he would have altered the course of English – and thus Western – history. It seems like such a huge turning point of history to rest on the body of one small infant.