Consanguinity
Transcript
Consanguinity:
Raise your hand if you’re the descendant of a cousin marriage? Anyone want to admit it? Guess what? Most of you should be raising your hands. Almost every single human being on planet earth is the result of at least a second cousin marriage at some point in their distant past.
First, before anyone jumps on me, cousin marriage includes those who share a recent ancestor, so a grandparent, great-grandparent, or a great-great grandparent and currently, worldwide up to 10% of marriages are between people who share a grandparent, or great-grandparent. Even the current king of England, Charles III, is the result of a cousin marriage, his parents, Elizabeth I and Prince Philip, were second cousins once removed through his great-grandfather, Christian IX of Denmark, who was her great-great grandfather. Elizabeth and Philip also happened to be third cousins through Victoria. Don’t worry, as second cousins they would only share a bit more than 3% of their DNA, the risk of inherited genetic issues was minimal. Almost every passed mentioned in this series thus far has been the result of a cousin marriage of some type, except the first three (Robert Curthose, Robert of Gloucester, and the Empress Matilda), and that’s only because the Norman house hadn’t been marrying with royal houses for long, by the next generation this was corrected.
So, why am I even talking about this? Well, you may have notice in a lot of episodes I discuss the subject ‘waiting for Papal dispensation’ due to consanguinity or affinity. It was a worry for Edward III and Philippa of Hainaut with regards to their oldest son, the Black Prince (since Joan was the Black Prince’s first cousin once removed. And you’ll remember Henry I having his nephew, William Clito’s, marriage to Sybilla of Anjou dissolved on the grounds of consanguinity (despite both of his children’s marriages being just as consanguineous since they were married to Sybilla’s siblings and the claim was through the line of descent he and Clito’s father shared). Consanguinity is the relation, by blood originally, between two people. In most of the west, the idea of this comes from Roman civil law. Marriages were prohibited if the couple were related by four degrees of consanguinity. For the Romans this would mean you count back one partner’s family tree until you get to the couple’s most recent common ancestor and then count forward on the other partner’s. Under Roman the Black Prince and his wife, Joan of Kent, had nothing to worry about. There are some additional complications with Roman law, but those don’t impact us while looking at the medieval period and later. The Catholic church originally followed this rule, four degrees. At least, until the 9th century, when they decided that seven degrees was the way to go. Oh, and instead of counting back to the common ancestor and forward to the other partner, they just counted back. And one more thing, being married to someone means their family is your family, so their sister is completely off limits, since she’s your sister, but also she should be off limits to your brother. And just one more little, tiny thing, if you’re someone’s godparent you’re now family as well, John of Gaunt had to deal with this in his third marriage since he was godfather to Kathryn Swynford’s daughter, Blanche. By being Blanche’s godfather he was at least in the church’s eye the brother of Kathryn. You may be able to see how this could be a problem. Nobility and royalty at this time was (as it is today) a small, stratified group. This would have made it impossible for most of them to marry without papal dispensation. Oh, and of course, the church got paid for these dispensations, someone has to think of the scribes, right? The cynic in the group might think the Catholic church was hoping for some extra funding since they were the only place in town to get these dispensations from, you know, since they’d never do anything questionable to raise funds.
Realising that the amount of paperwork might get a little intense if they kept it up the 4th Lateran Council changed a few things. You still had to count up to closest ancestor, but it was no longer seven degrees, but moved back to four. So, the Black Prince and Joan would still need dispensation (their closest ancestor, Edward I was three degrees removed from the Black Prince and two from Joan), but William Clito’s marriage to Sybilla of Anjou wouldn’t have been able to be challenged on the grounds of consanguinity (they were only related in the sixth degree on Clito’s side and the fifth on Sybilla’s). To think how much trouble that would have caused Henry I, I’m trying not to laugh at his imagined pain.
An interesting aside, while the church could give dispensation to allow marriages within the prohibited degree of consanguinity, it could also annul marriages even after this dispensation had been received. Especially in cases where the couple didn’t want to be married to each other any longer. I mentioned in the Empress Matilda’s final episode that her son, the future Henry II, would marry Eleanor of Aquitaine. At the time Henry and Eleanor met she was the queen of France through her marriage to the French king Louis VII. Louis and Eleanor had been married for 14 years, I can’t find evidence of them receiving dispensation prior to their marriage, but they did receive it in 1149. However, even with that Louis and Eleanor were able to procure an annulment (a process of dissolving a marriage as though it had never existed), though their two daughters were declared legitimate. For reference Louis and Eleanor were third cousins once removed (I’ll include a link to an easy to read consanguinity chart in the show notes). I will point out that even if Eleanor and Louis had gotten papal dispensation prior to their marriage it may not have prevented their annulment. The church’s reason for changing the rules regarding consanguinity at the 4th Lateran Council is often claimed to be a spate of annulments (or divorces, in this period those are the same thing), Louis’ great-great-great grandfather, Robert II had been forced to repudiate his wife Bertha on the same grounds. I imagine they were actually getting angry notes from all the kings of western Europe who were struggling to marry their sons and daughters off without breaking marital rules. In fact, the daughters of kings were being married off to counts, which was considered a bit of a step down, just to avoid marrying a very distant cousin. Well, there was another, actually, more important reason. The church was transitioning marriage from a more secular process performed by the church to a sacrament, which it still is today. By making it a sacrament they would make it harder to dissolve. By changing the degrees of kinship that a couple could have the church was making sure couples couldn’t use this as an easy get out of jail…wait, marriage card.
What does science say about this? I’ve spent a bit of time looking at this, partially because when Googling ‘consanguinity’ in scholar one finds a lot of scholarly articles related to the genetic issues with cousins marrying each other. For first cousins there are risks, recessive traits are more likely to be expressed in closely related individuals and some of these are detrimental, say Cystic fibrosis and tay-sachs. Both of these can occur in families who aren’t closely related, but become more likely if a family is a carrier and marry close relatives. There’s even an example in royalty of how badly things can go with ongoing marriages between close family members. Charles II of Spain, king of Spain from 1665-1700 had multiple medical issues including epilepsy, likely as a result of his parents being an uncle-niece marriage at the end of a long line of cousin and uncle-niece marriages. A single incident of first cousin marriage isn’t likely to cause major issues, say Charles Darwin and his wife Emma Wedgwood or Queen Victoria and Prince Albert. But what about marriages between more distantly related cousins? Until recently most marriages in Iceland were between third or fourth cousins. Second cousins share only 3% of their genetics, so the risks of serious medical issues with their children drops compared to first cousin marriages. Every state in the US and most of the rest of the western world allows second cousin marriage and 19 states, plus Canada, Australia, all of South America, and most of Europe allow first cousin marriage. In general I think the royalty of Europe throughout history show that marrying a second or more distantly related cousin isn’t the end of the world, though, it can make family reunions awkward, or great match-making events.
Sources:
https://www.jstor.org/stable/j.ctt5vm2g7
https://link.springer.com/chapter/10.1007/978-1-137-05262-9_10
https://daily.jstor.org/the-genetics-of-cousin-marriage/
https://upload.wikimedia.org/wikipedia/commons/0/0d/Table_of_Consanguinity_showing_degrees_of_relationship.svg
