Habsburgs & Genetics

Hey everyone. So, we know that the Habsburgs were famously adept at strategic marriages, and this had the consequence of different brances of the House of Habsburg frequently intermarrying to retain power. As time went on, the gene pool got more limited, until eventually the very strategy that they used to hold power rendered Charles II of Spain unable to produce an heir. The War of the Spanish Succession happened, the Bourbons got Spain, and this practice became a lot less relevant until eventually the Austrian Habsburg Marie Antoinette would marry the French Bourbon Louis XVI.

Is there a way that the Habsburgs could have pursued a more sustainable marriage-succession policy? Maybe an earlier Pragmatic Sanction? When would a Pragmatic Sanction have been most viable -- perhaps after an alternate Thirty Years' War, which ends in Catholic League victory (or Protestant League secession from the HRE), and the House of Habsburg is secured as a hereditary Imperial dynasty?
 
Easy just have them marry in the beginning to much more house and always have a couple people branch off and form new house and do not have as much inter marriage
 
They just need a little more luck. Philip II and Philip IV had no surviving sons with their French wifes, who were not closely related to them, but they had surviving sons with their nieces.
 
The Reformation was responsible for the loss of many otherwise decent German brides. Even keeping Luther's 1517 protest isn't necessarily a bad thing. Georg the Bearded of Saxony had two sons who would presumably leave issue (and his nephew, Severinus, was being raised alongside Ferdinand I's kids in Innsbruck). Karl Viktor and Philipp Magnus of Brunswick were killed at Sievershausen and were firebrand sort Catholics. Kasimir of Ansbach was likewise a Catholic - his death led to his kids being given into the custody of his brother, Georg der Fromme (who was Protestant) and this in turn led to the Electoral Wittelsbachs going Protestant.

Prevent a few deaths and a few more IMPORTANT Catholic houses in Germany and you might see the Habsburgs spreading their pool instead of relying solely on Bavaria.

As to the intermarriage between the branches, under Karl V-Ferdinand they got on. Felipe II-Maximilian II's relations were sort of okay. Felipe II-Rudolf II not so good. Felipe III-Ferdinand II were good again. Felipe IV-Ferdinand II not so much (IIRC there was an anecdote mentioned where Felipe wants to know why Ferdinand needs money for more troops when Spain has just sent him some last month). Felipe IV-Ferdinand III/Leopold I good again.
The avuncular intermarriages generally took place when one branch was teetering on the brink of extinction (Felipe II married his niece because after 3 marriages he had no male heirs left; Felipe IV married his niece because his male heir had died; Leopold married his niece because she was the heir to Spain should something happen to her brother). Felipe III married his cousin. He had three sons, none of whom married another Habsburg (Felipe IV did as a second wife, but that was only after his son and brothers were both dead).

And if we're classing uncle-niece marriages as disgusting/genetically problematic, we should include other marriages the Habsburgs contracted (oft-overlooked because one partner didn't have the surname Habsburg): Ferdinand II and Anna Caterina Gonzaga (had three kids, a future empress-consort among them); Karl of Steyr and Maria Anna of Bavaria (had over a dozen kids, two queens of Poland, a queen of Spain and an emperor among them); Maria Anna of Austria (married her uncle, the elector of Bavaria)
 
And if we're classing uncle-niece marriages as disgusting/genetically problematic, we should include other marriages the Habsburgs contracted (oft-overlooked because one partner didn't have the surname Habsburg): Ferdinand II and Anna Caterina Gonzaga (had three kids, a future empress-consort among them); Karl of Steyr and Maria Anna of Bavaria (had over a dozen kids, two queens of Poland, a queen of Spain and an emperor among them); Maria Anna of Austria (married her uncle, the elector of Bavaria)

Francis and Maria-Theresa was the worst one. They were double first cousins, which is genetically equivalent to full siblings.
 
Francis and Maria-Theresa was the worst one. They were double first cousins, which is genetically equivalent to full siblings.
Double first cousins are not as closely related as full siblings thanks to gene recombination-they share 25% of their DNA, like half-siblings or uncle/aunt-nephew/niece. The most inbred Habsburg ever was not Carlos II but his niece Maria Antonia of Austria-her parents (Leopold I and Maria Margaret of Spain) were uncle-niece, first cousins and second cousins at the same time.
Still, Ptolemaid dynasty survived 300 years with much worse inbred.
 

Vitruvius

Donor
I think there's a number of factors that don't just apply to the Habsburgs, though they were obviously one of the worst manifestations. The big one was the limited number of Catholic houses left after the reformation which shrank the pool in Germany. Then, ironically, the fecundity of Ferdinand I and Anna, their daughters married into the house of Bavaria, Mantua and Tuscany such that the remaining Catholic houses ended up at least somewhat related going into the 17th century. This also brought about the first round of avuncular marriages when their sons Ferdinand II and Charles II both married nieces as the pool of available Catholic brides was so small (especially once you eliminate the French, who had no prospects available in the late 16th century as they were going through a succession crisis of their own). Which leads to another point, many other houses, such as Bavaria and France were almost just as bad as the Habsburgs. As pointed out double first cousins statistically share about the same amount of DNA as uncles and nieces so Philip IV's avuncular marriage to Mariana of Austria is no worse really that Louis XIV's to Maria Theresa of Spain. Not to mention that Marie de' Medici, as a grand-daughter of Ferdinand I, was a first cousin of Philip IV's mother, Margaret, thus Louis XIV's parents Anne of Austria and Louis XIII were already second cousins.

Bavaria was, I think, worse; Albert V was a second cousin once removed to Ferdinand's daughter Anna, their son William V married Renata of Lorraine who was his second cousin, again through a Habsburg line (maternal descendants of Philip the handsome), their son Maximilian I first married his first cousin Elisabeth of Lorraine then his niece Maria Anna of Austria (who's father Ferdinand II was the child of an avuncular marriage between Charles II of Austria and Maria Anna of Bavaria and so she was also Maximilian's first cousin once removed), their son Ferdinand Maria, somehow turned out just fine and married Henriette Adelaide of Savoy who, as a grand-daughter of Marie de' Medici and Catherine Michelle of Spain, already had both Spanish and Austrian Habsburg blood, their son Max Emmanuel then married Maria Antonia of Austria, his second cousin (who was herself the product of an avuncular Habsburg marriage). So it's not surprising that their son Jose Ferdinand died young as he had a pedigree just as bad as Charles II. Thankfully Max Emmanuel then married a Sobieski princess injecting desperately needed fresh blood that probably saved the Bavarian Wittlesbachs from their own extinction event.

Anyways, point of this is that this issue wasn't limited to the Habsburgs, if you dig around all the major Catholic houses had this problem, it's just not as evident because they didn't always have the same name. Perhaps what made the difference in other cases is that the other houses managed to get a break every 2nd or 3rd generation and 'only' marry a second cousin or at least someone more distantly related than niece or 1st cousin. I think the Habsburgs lost that opportunity only though a few unfortunate deaths, Balthasar Carlos, for example, was from parents only distantly related (2nd cousins) and his marriage to Mariana would have been 'only' to a first cousin. Likewise Ferdinand IV of Austria could have married someone more distantly related than his brother Leopold's OTL marriage to his own niece. They really needed to get some fresh blood in the early 17th century after the previous series of avuncular and first cousin marriages. The only real move where I think there was a better choice available was Philip IV's marriage to Mariana, if he had married someone else, say Anna de' Medici or Eleonora Gonzaga, or maybe even Isabella Clara of Tyrol as a second wife he could have saved his line. This in turn would likely have helped the Austrian line as well.
 
Double first cousins are not as closely related as full siblings thanks to gene recombination-they share 25% of their DNA, like half-siblings or uncle/aunt-nephew/niece. The most inbred Habsburg ever was not Carlos II but his niece Maria Antonia of Austria-her parents (Leopold I and Maria Margaret of Spain) were uncle-niece, first cousins and second cousins at the same time.
Still, Ptolemaid dynasty survived 300 years with much worse inbred.

Double first cousins have the same four grandparents.

Maria Antonia? Yikes!!
 
The hapsburgs looked like the "amerimutt/"le 56%" memes but IRL. Obviously nothing good was going on with those genes. Maybe with better marriages you get hapsburgs that look human or at least within the broader hominid family instead of like the -666% face.
 
The Reformation was responsibl
Ie for the loss of many otherwise decent German brides. Even keeping Luther's 1517 protest isn't necessarily a bad thing. Georg the Bearded of Saxony had two sons who would presumably leave issue (and his nephew, Severinus, was being raised alongside Ferdinand I's kids in Innsbruck). Karl Viktor and Philipp Magnus of Brunswick were killed at Sievershausen and were firebrand sort Catholics. Kasimir of Ansbach was likewise a Catholic - his death led to his kids being given into the custody of his brother, Georg der Fromme (who was Protestant) and this in turn led to the Electoral Wittelsbachs going Protestant.

Prevent a few deaths and a few more IMPORTANT Catholic houses in Germany and you might see the Habsburgs spreading their pool instead of relying solely on Bavaria.

I see. I can appreciate that the Habsburgs were a very strongly Catholic house, and that marriage to a Catholic dynasty meant officiation in a Catholic ceremony and therefore legitimised the Church as some sort of authority over your bloodline. And at various times the Church itself has specifically forbidden marriage to non-Catholics (although I don't know if that's a modern thing, or if it was true at the time of the HRE; it might explain the diplomatic implications of excommunicating entire nations, but like, I don't know).

What if, hypothetically, the Spanish New World was divided into hereditary fiefdoms under a royal-appointed Viceroy? I know this happened more or less OTL, but if instead of the Casta System, the Spanish encouraged natives to Christianise and marry Europeans in order to assimilate them? I know that Limpieza de Sangre was a thing, but even still, common conversos were encouraged to intermarry with common Spaniards in order to "breed out" Jewishness/Moorishness, and enforce the assimilation of Jewish/Muslim communities. Could the Spanish nobility in the New World intermarry with Christianised Aztec or Inca lords?
I know that in the Kingdom of Kongo, Afonso I converted to Christianity after the arrival of Portuguese merchants and missionaries. Kongo went from an elective monarchy to a hereditary one, and I think I remember reading that Afonso or another Kongolese king took a Portuguese consort, but I'm not 100% sure about that. Either way, Kongo was able to receive and send ambassadors to the Pope, and participate in the politics of Christendom, even if it was only on the periphery. But how likely would it be for the Conquistadores to intermarry with a Christianised indigenous American elite, as they established feudal dynasties of their own in America? Clearly, being within Christendom isn't a prerequisited for participating in the politics of Christendom.
 
Francis and Maria-Theresa was the worst one. They were double first cousins, which is genetically equivalent to full siblings.

Uh no. Double first cousins would imply that both their parents were siblings of the other partner's parents. François' closest relation to Maria Theresia was through his paternal grandmother (Eleonora Maria Josepha of Austria) who was half-sister to Maria Theresia's paternal grandfather. Ergo sevond HALF cousins

I see. I can appreciate that the Habsburgs were a very strongly Catholic house, and that marriage to a Catholic dynasty meant officiation in a Catholic ceremony and therefore legitimised the Church as some sort of authority over your bloodline. And at various times the Church itself has specifically forbidden marriage to non-Catholics (although I don't know if that's a modern thing, or if it was true at the time of the HRE; it might explain the diplomatic implications of excommunicating entire nations, but like, I don't know).

What if, hypothetically, the Spanish New World was divided into hereditary fiefdoms under a royal-appointed Viceroy? I know this happened more or less OTL, but if instead of the Casta System, the Spanish encouraged natives to Christianise and marry Europeans in order to assimilate them? I know that Limpieza de Sangre was a thing, but even still, common conversos were encouraged to intermarry with common Spaniards in order to "breed out" Jewishness/Moorishness, and enforce the assimilation of Jewish/Muslim communities. Could the Spanish nobility in the New World intermarry with Christianised Aztec or Inca lords?
I know that in the Kingdom of Kongo, Afonso I converted to Christianity after the arrival of Portuguese merchants and missionaries. Kongo went from an elective monarchy to a hereditary one, and I think I remember reading that Afonso or another Kongolese king took a Portuguese consort, but I'm not 100% sure about that. Either way, Kongo was able to receive and send ambassadors to the Pope, and participate in the politics of Christendom, even if it was only on the periphery. But how likely would it be for the Conquistadores to intermarry with a Christianised indigenous American elite, as they established feudal dynasties of their own in America? Clearly, being within Christendom isn't a prerequisited for participating in the politics of Christendom.

Marriage to non-Catholics wasn't forbidden per se, it was simply a case of said non-Catholic (i.e. Protestant) was viewed as being outside of the Communion of the Church and thus a heretic, and a conversion to Catholicism was necessary (several Habsburg matches with Protestants foundered on this, Leopold I (and Josef I) to a daughter of the king of Denmark (both girls refused to convert in these instances), Karl VI to Karoline of Ansbach flat out told the emperor he was barking up the wrong tree and even his wife, Elisabeth Christine of Brunswick stalled until basically beaten into it by her granddad, before converting (negotiations started in 1704 but were hung up on the conversion issue until 1707).

As to the idea of a Habsburg marrying some Christian Inca/Aztec princess with the pope's sanction? It would be seen with a degree of snobbery by Europe's houses as "unequal" (see how the king of Saxony treated the queen of Hawai'i at Queen Victoria's Diamond Jubilee) - and probably in the same light as if he'd married a Muslim or Jewish converso (if not worse, probably).

Please note though @The_Persian_Cat , I could be wrong about how it might be seen regarding her religion, but I don't think I'm too far wrong about it being looked down on with regards to unequal/unsuitable rank and race.

Welcome to the board, BTW
 

Vitruvius

Donor
I think you have to make a distinction between Catholic aristocracy and Catholic royalty, especially going into the later half of the 17th century. With the rise of Absolutism and the divine right of Kings it increasingly became a closed system, marriage wise, where royalty had to marry other royalty. The difference between a King and a mere Duke and between a sovereign Duke (say of Savoy or Parma) and just some Count of Baron of some fief of some other monarch began to become more pronounced. When you shrink the pool even further in that way things naturally get tricky. So expanding the world of the Catholic aristocracy maybe produces a more (genetically) robust noble class but the Royal families probably remain inbred.

Your best bet to for a broad based solution is to simply have the Pope refuse to grant indulgences. This was eventually done OTL in the late 19th century but by then advances in health and decreases in infant mortality, and the increase of Royal houses, especially in Germany coming out of the counter-reformation (conversion of Wettins and Wittlesbachs), meant there were plenty of opportunities even if you were no longer allowed to marry your niece. Also the marriage alliances as a form of diplomacy decreased in value somewhat. So obviously there's a reason it wasn't done until so late. But maybe get a more aggressive Pope, perhaps with some basis in counter-reformation doctrine and essentially ban the practice, at least of avuncular or 1st cousin marriages and force the Royals to branch out more.
 
The big thing is 16th century Europe wide separation of Monarchs from their nobilities as you saw increasingly absolute states develop. If you look at Medieval French Queens a narrow majority came from noble, non-royal families and while that wasn't an enormous genetic pool it was much bigger than the "crowned heads only" policy adopted in the 17th-19th centuries.

How to prevent that separation though is a difficult question.
 
How large does a population have to be again to avoid inbreeding and the species dying out? 500, isn't it? Of course, these times didn't know about genetics.
 
How large does a population have to be again to avoid inbreeding and the species dying out? 500, isn't it? Of course, these times didn't know about genetics.

I'm guessing those figures relate at least in part to the danger of a population dying out because it's not diverse enough to withstand contagions. That would be a more salient factor if we were only looking at the inbreeding population, and nobody else, but the Hapsburgs were only a small part of a larger society, so that should mitigate that danger. Most potential carriers wouldn't be nearly so inbred.
 

Philip

Donor
How large does a population have to be again to avoid inbreeding and the species dying out? 500, isn't it?

It depends on how genetically diverse the population is to begin, but 500 seems like a fair estimate. One hundred unrelated individuals probably had a better chance than 500 effective siblings. The population also has a better chance of there is some planning to optimize genetic diversity. Of course, genetic diversity does not seem to have been a goal for the Spanish Habsburgs.

Pitcairn shows that rather small human populations are viable, at least for a while.
 

Vuu

Banned
Charles II was just a case of really bad luck

Charles' sister was completely fine
 
Of course, genetic diversity does not seem to have been a goal for the Spanish Habsburgs.

As Hans Bankl (contemporary Austrian historian) puts it, the only condition for a marriage was that they had sixteen noble great-great-grandparents. They seemed to think: "And if some ancestor appeared twice in the family tree, twice as well!"
 
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