Uploaded May 2026 | Updated September 2026, 2 weeks ago
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Royals throughout history are notorious for inbreeding. I utter the phrase ‘married her cousin’ disturbingly frequently. They wanted to keep their wealth and power in the family, and found nothing more distasteful than marrying a commoner. But they didn’t understand that the incessant incest was wreaking havoc on their DNA. Causing many tragically unwell individuals, and countless children who couldn’t survive childhood. I’ve done episodes on the tangled family trees of two of the most famously inbred families, the Hapsburgs and the Bourbons. But they weren’t the only dynasties in on the cousin kissing and sister swapping. Today let’s use the Coefficient of inbreeding, or COI to count down the top 10 individual monarchs who rank the highest in inbreeding. What is inbreeding and how do we quantify and rank it?
10. Maria II, Queen of Portugal, COI 9.89
9. Felipe II, King of Spain, COI 11.44
8. Victor Emmanuel III, King of Italy, COI 15.32
7. Ferdinand I, Emperor of Austria, COI 17
6. João VI, King of Portugal, COI 18.73
5. Sebastião, King of Portugal, COI 20.25
4. Felipe III, King of Spain & Portugal, COI 21.26
3. Isabel II, Queen of Spain, COI 21.41
2. Carlos II, King of Spain, COI 25.36
1. Alfonso XII, King of Spain, COI 26.67
Honorable mentions:
14. Louis XV, King of France COI 9.55
13. Edward VII, King of the UK had a COI of 9.57
Maria Antonia, Archduchess of Austria & Electress of Bavaria, COI 30.53
Please consider supporting me at patreon.com/LindsayHoliday
Check out the History Tea Time Podcast:
Spotify: open.spotify.com/show/7iW8gOI5wb5TNFAIhBd9Om?si=46aeeacd64214ac0
Apple: podcasts.apple.com/us/podcast/history-tea-time/id1619978406
Follow me on Facebook: facebook.com/profile.php?id=100091781568503
Instagram: instagram.com/historyteatimelindsayholiday
Music: Brandenburg Concerto No4-1 BWV1049 - Classical Whimsical by Kevin MacLeod is licensed under a Creative Commons Attribution 4.0 license. creativecommons.org/licenses/by/4.0
Source: incompetech.com/music/royalty-free/index.html?isrc=USUAN1100303
Artist: incompetech.com
For business inquiries, please contact LindsayHoliday@fixated.com
Go to buyraycon.com/HISTORYTEATIMEOPEN to get 15% off Raycon Earbuds!
Royals throughout history are notorious for inbreeding. I utter the phrase ‘married her cousin’ disturbingly frequently. They wanted to keep their wealth and power in the family, and found nothing more distasteful than marrying a commoner. But they didn’t understand that the incessant incest was wreaking havoc on their DNA. Causing many tragically unwell individuals, and countless children who couldn’t survive childhood. I’ve done episodes on the tangled family trees of two of the most famously inbred families, the Hapsburgs and the Bourbons. But they weren’t the only dynasties in on the cousin kissing and sister swapping. Today let’s use the Coefficient of inbreeding, or COI to count down the top 10 individual monarchs who rank the highest in inbreeding. What is inbreeding and how do we quantify and rank it?
10. Maria II, Queen of Portugal, COI 9.89
9. Felipe II, King of Spain, COI 11.44
8. Victor Emmanuel III, King of Italy, COI 15.32
7. Ferdinand I, Emperor of Austria, COI 17
6. João VI, King of Portugal, COI 18.73
5. Sebastião, King of Portugal, COI 20.25
4. Felipe III, King of Spain & Portugal, COI 21.26
3. Isabel II, Queen of Spain, COI 21.41
2. Carlos II, King of Spain, COI 25.36
1. Alfonso XII, King of Spain, COI 26.67
Honorable mentions:
14. Louis XV, King of France COI 9.55
13. Edward VII, King of the UK had a COI of 9.57
Maria Antonia, Archduchess of Austria & Electress of Bavaria, COI 30.53
Please consider supporting me at patreon.com/LindsayHoliday
Check out the History Tea Time Podcast:
Spotify: open.spotify.com/show/7iW8gOI5wb5TNFAIhBd9Om?si=46aeeacd64214ac0
Apple: podcasts.apple.com/us/podcast/history-tea-time/id1619978406
Follow me on Facebook: facebook.com/profile.php?id=100091781568503
Instagram: instagram.com/historyteatimelindsayholiday
Music: Brandenburg Concerto No4-1 BWV1049 - Classical Whimsical by Kevin MacLeod is licensed under a Creative Commons Attribution 4.0 license. creativecommons.org/licenses/by/4.0
Source: incompetech.com/music/royalty-free/index.html?isrc=USUAN1100303
Artist: incompetech.com
For business inquiries, please contact LindsayHoliday@fixated.com
