In previous times, mainly due to keeping power, money and such in the family, there were many inter-family marriages in royal circles.

https://en.wikipedia.org/wiki/Royal_intermarriage

Many of them have already been discussed over here, but it keeps my interest
Especially when I was busy with the BRF weddings, you can trace several inter-family marriages. Both 1st cousins as further removed.

Based on genetics, it is logical that closely related people can lead to offspring with disorders, diseases and / or enhancement of physical characteristics. An increased risk. In particular if this inbreeding happens over several generations.

Many are familiar with the well known inbreed case of the (Spanish) Habsburg, with ultimate example Carlos II.
https://en.wikipedia.org/wiki/Charles_II_of_Spain

Knud, Hereditary Prince of Denmark (Knud Christian Frederik Michael)(1900 � 1976), was the younger son and child of Christian X and Alexandrine of Mecklenburg-Schwerin. He married his 1st cousin Princess Caroline-Mathilde of Denmark (1912 � 1995).  She was a daughter of Frederick VIII's son Harald. Knud and Caroline-Mathilde had three children: Princess Elisabeth, Prince Ingolf and Prince Christian.

Charlotte (Charlotte Adelgonde �lise/Elisabeth Marie Wilhelmine)(1896 � 1985) reigned as Grand Duchess of Luxembourg from 1919 until her abdication in 1964. She was the second daughter of Grand Duke Willem IV and his wife, Marie Anne of Portugal. She married her (maternal) 1st cousin Prince F�lix of Bourbon-Parma (F�lix Marie Vincent)(1893-1970). Prince F�lix was one of the 24 children of the deposed Robert I, Duke of Parma, being the duke's sixth child and third son by his second wife, Maria Antonia of Portugal. Marie Anne and Maria Antonia were sisters.


Princess Bona of Savoy-Genoa (Maria Bona Margherita Albertina Vittoria)(1896 �1971), was a daughter of Prince Thomas, Duke of Genoa and Princess Isabella of Bavaria. She married her 2nd cousin Prince Konrad of Bavaria (Konrad Luitpold Franz Joseph Maria Prinz von Bayern)(1883 � 1969) He was the youngest son of Prince Leopold of Bavaria and Archduchess Gisela of Austria.


Prince Gustaf Adolf Oscar Fredrik Arthur Edmund, Duke of V�sterbotten (1906 �1947) eldest son of the then Prince Gustaf Adolf and his first wife Princess Margaret (n�e princess Margaret of Connaught/GB). He married his second cousin, Princess Sibylla of Saxe-Coburg and Gotha (Sibylla Calma Marie Alice Bathildis Feodora)(1908 � 1972), daughter of Charles Edward, Duke of Saxe-Coburg and Gotha. Margaret and Charles had been 1st cousins.

Princess Sophie of Greece and Denmark (Greek: Σοφία)(1914 � 2001) She was the fourth child and youngest daughter of Prince Andrew of Greece and Denmark and Princess Alice of Battenberg. The Duke of Edinburgh is her younger brother. Although the youngest of four sisters, Sophie was the first to wed, marrying her second cousin-once-removed Prince Christoph of Hesse (1901�1943). They had 5 children.

Sophie's second marriage was to Prince George William of Hanover (1915-2006) (her second cousin through Christian IX and third cousin through Victoria, having also been a first cousin once removed of Sophie's first husband, Christoph, in descent from Victoria, Princess Royal) They had 3 children.

Grand Duchess Elena Vladimirovna of Russia (1882 � 1957) the only daughter and youngest child of Grand Duke Vladimir Alexandrovich of Russia and Duchess Marie of Mecklenburg-Schwerin. She married her 2nd cousin Prince Nicholas of Greece and Denmark (Greek: Πρίγκιπας Νικόλαος της Ελλάδας και της Δανίας)(1872 �1938). His mother Olga Constantinovna of Russia and her father Vladimir Alexandrovich of Russia were 1st cousins. Both Elena as her husband Nicholas were first cousins of Emperor Nicholas II of Russia.The couple had 3 daughters.

Olav V of Norway (born Prince Alexander of Denmark)(1903 � 1991) Olav was the only child of King Haakon VII of Norway (n�e Prince Carl of Denmark) and Maud of Wales. He became heir apparent to the Norwegian throne when his father was elected King of Norway in 1905. In 1929 he married his first cousin Princess M�rtha of Sweden  (M�rtha Sofia Lovisa Dagmar Thyra)(1901 � 1954) with whom he had two daughters, Ragnhild and Astrid and one son, Harald. M�rtha was the second child of Prince Carl of Sweden, Duke of V�sterg�tland, and his wife Princess Ingeborg of Denmark. Her mother was the younger sister of King Christian X of Denmark and of King Haakon VII of Norway.


Princess Margaretha of Sweden (Margaretha Sofia Lovisa Ingeborg)(1899 �  1977) was a member of the Swedish Royal Family and the Danish Royal Family by marriage. Margaretha was the eldest child and daughter of Prince Carl, Duke of V�sterg�tland, and Princess Ingeborg of Denmark. She was the elder sister of Crown Princess M�rtha of Norway and Queen Astrid, Queen Consort of the Belgians. In 1919 she was married to Prince Axel of Denmark (Danish: Prins Axel Christian Georg til Danmark)(1888 � 1964), her maternal first cousin once removed. The marriage was a love match; her mother remarked that the couple were so much in love that they could not be left alone in a furnished room.

Princess Ingrid of Sweden (Ingrid Victoria Sofia Louise Margareta)(1910 � 2000) the daughter of King Gustaf VI Adolf of Sweden and his first wife, Princess Margaret of Connaught. She married the later
King Frederik IX of Denmark. Frederik IX (Christian Frederik Franz Michael Carl Valdemar Georg)(1899 � 1972) was the elder son of King Christian X of Denmark and Alexandrine of Mecklenburg-Schwerin. They were related in several ways. As descendants of Oscar I of Sweden, they were third cousins. Through Leopold, Grand Duke of Baden, they were third cousins. And finally through Paul I of Russia, Frederik was a fourth cousin of Ingrid's mother.

Grand Duchess Xenia Alexandrovna of Russia (Russian: Ксения Александровна Романова)(1875 � 1960) was the elder daughter and fourth child of Tsar Alexander III of Russia and Empress Maria Feodorovna of Russia (n�e Princess Dagmar of Denmark). She married her paternal first cousin once removed Grand Duke Alexander Mikhailovich of Russia (1866 � 1933). Xenia and Alexander had seven children together, one daughter followed by six sons.

Origin Victoria of Great Britain (besides the ones already mentioned above).

Prince Albert William Henry of Prussia (German: Albert Wilhelm Heinrich)(1862 � 1929) was the third child and second son of eight children born to Crown Prince Frederik (later Emperor Frederik III), and Victoria, Princess Royal of the United Kingdom (later Empress Victoria and in widowhood Empress Frederick), eldest daughter of the British Queen Victoria. Henry married Princess Irene of Hesse and by Rhine, his first cousin (at maternal side). The marriage produced three children.

Princess Alexandra, 2nd Duchess of Fife (Alexandra Victoria Alberta Edwina Louise)(1891 �1959), daughter of Louise, Princess Royal (Louise Victoria Alexandra Dagmar)(1867 �1931) who was the third child and the eldest daughter of the British king Edward VII and Alexandra of Denmark & Alexander William George Duff, 1st Duke of Fife (1849 �1912). Alexandra married her first cousin once removed, Prince Arthur of Connaught (1883 � 1938), and had issue.


Princess Maud of Wales (Maud Charlotte Mary Victoria) (1869 � 1938)  She was the third daughter and fifth child of Albert Edward, Prince of Wales, the eldest son of Queen Victoria, and Alexandra, Princess of Wales, the eldest daughter of King Christian IX of Denmark. Maud married her 1st (maternal) cousin Prince Carl of Denmark (the later King Haakon VII) (1872-1957). Prince Carl was the second son of Queen Alexandra's eldest brother, Crown Prince Frederick of Denmark, and Princess Louise of Sweden. The only child of Maud and Carl, Alexander (the later Olav V), also married a 1st cousin Princess M�rtha of Sweden. The daughter of a sister of Carl (also see above in an earlier post).


Princess Victoria of Hesse and by Rhine (1863-1950), the eldest daughter of Louis IV, Grand Duke of Hesse and by Rhine (1837�1892), and his first wife Princess Alice of the United Kingdom (1843�1878), daughter of Queen Victoria and Prince Albert of Saxe-Coburg and Gotha. She married her first cousin once removed Prince Louis of Battenberg (1854-1921). Louis was a member of a morganatic branch of the Hessian royal family and was a 1st cousin to Victoria's father.


Ernest Louis Charles Albert William (German: Ernst Ludwig Karl Albrecht Wilhelm)(1868 � 1937) was the last Grand Duke of Hesse and by Rhine, reigning from 1892 until 1918. He was the elder son of Louis IV, Grand Duke of Hesse and by Rhine and Princess Alice of the United Kingdom, daughter of Queen Victoria and Prince Albert of Saxe-Coburg and Gotha. Ernest Louis firstly married his maternal first cousin, Princess Victoria Melita of Saxe-Coburg and Gotha ("Ducky") (1876-1936), the daughter of his mother's brother, Prince Alfred.Ernest Louis  and Victoria Melita had two children. Their marriage was unhappy due to differences in temperament and attitude. They were divorced in 1901.


Victoria Melita of Saxe-Coburg and Gotha ("Ducky") (1876-1936), the daughter of Prince Alfred, Duke of Edinburgh, the second son of Queen Victoria and Grand Duchess Marie Alexandrovna, the only surviving daughter of Alexander II of Russia and Marie of Hesse. She secondly, after her divorce from Ernest Louis of Hesse and by Rhine, married another 1st cousin Grand Duke Kirill Vladimirovich of Russia (1876 � 1938).  Kirill was the son of  Grand Duke Vladimir Alexandrovich, the third son of Tsar Alexander II of Russia and Grand Duchess Maria Pavlovna, n�e Duchess Marie Alexandrine of Mecklenburg. According to the stories: In her teens Victoria fell in love with her maternal first cousin Grand Duke Kirill Vladimirovich of Russia, but the disapprobation of marriage between first cousins of his faith, Orthodox Christianity, discouraged their romance. Bowing to family pressure, Victoria married her paternal first cousin, Ernest Louis, Grand Duke of Hesse and by Rhine.


Gottfried, 8th Prince of Hohenlohe-Langenburg (German: Gottfried Hermann Alfred Paul Maximilian Viktor F�rst zu Hohenlohe-Langenburg)(1897 � 1960) was the only surviving son of Ernst II, Prince of Hohenlohe-Langenburg and Princess Alexandra of Saxe-Coburg and Gotha (1878�1942)(daughter of Alfred, Duke of Saxe-Coburg and Gotha and Grand Duchess Maria Alexandrovna of Russia).  Gottfried married Princess Margarita of Greece and Denmark. Margarita was the daughter of Prince Andrew of Greece and Denmark and his wife, Princess Alice of Battenberg. Gottfried and Margarita are second cousins once removed through Queen Victoria and third cousins through Nicholas I of Russia. Many years later, Margarita's much younger brother Philip would marry Gottfried's distant cousin Elizabeth, daughter of King George VI.They had 6 children.

Princess Marie Melita of Hohenlohe-Langenburg (German: Marie Melita Leopoldine Viktoria Feodora Alexandra Sophie)(1899-1967) Daughter of Ernst II, Prince of Hohenlohe-Langenburg and Princess Alexandra of Saxe-Coburg and Gotha (1878�1942). Marie Melita married her second cousin, Wilhelm Friedrich, Hereditary Prince of Schleswig-Holstein-Sonderburg-Gl�cksburg, the only son of Friedrich Ferdinand, Duke of Schleswig-Holstein and his wife Princess Karoline Mathilde of Schleswig-Holstein-Sonderburg-Augustenburg. They had 4 children.


Prince Gustaf Adolf Oscar Fredrik Arthur Edmund, Duke of V�sterbotten (1906 �1947),  the eldest son of the then Prince Gustaf Adolf and his first wife Princess Margaret of Connaught. He he married his second cousin, Princess Sibylla of Saxe-Coburg and Gotha (1908-1972), daughter of Charles Edward, Duke of Saxe-Coburg and Gotha. They had 5 children.


Prince Arthur of Connaught (Arthur Frederick Patrick Albert)(1883 � 1938), the only son of Prince Arthur, Duke of Connaught and Strathearn, third son of Queen Victoria and Prince Albert of Saxe-Coburg and Gotha and Princess Louise Margaret of Prussia. Prince Arthur married his cousin Princess Alexandra, 2nd Duchess of Fife (1891 � 1959). see above


Princess Alice of Albany (Alice Mary Victoria Augusta Pauline) (1883 � 1981), daughter of  Prince Leopold, Duke of Albany, the youngest son of Queen Victoria and Prince Albert of Saxe-Coburg and Gotha and Princess Helena of Waldeck and Pyrmont.  She had one brother, Prince Charles Edward, Duke of Albany (1884�1954) and later reigning Duke of Saxe-Coburg and Gotha (1900�1918). Princess Alice of Albany married her second cousin once-removed, Prince Alexander of Teck, the brother of Princess Mary, the Princess of Wales (later Queen Mary, consort of George V).


Friedrich Josias, Prince of Saxe-Coburg and Gotha (Friedrich Josias Carl Eduard Ernst Kyrill Harald)(1918 � 1998) was the head of the Ducal Family of Saxe-Coburg and Gotha and titular Duke of Saxe-Coburg and Gotha from 1954 until his death.The third son and youngest child of Charles Edward, Duke of Saxe-Coburg and Gotha, and Princess Victoria Adelaide of Schleswig-Holstein-Sonderburg-Gl�cksburg. Friedrich Josias firstly married his (maternal) first cousin Countess Viktoria-Luise of Solms-Baruth (1921 � 2003) (daughter of Count Hans of Solms-Baruth and Princess Karoline Mathilde of Schleswig-Holstein-Sonderburg-Gl�cksburg). This marriage ended in divorce on 19 September 1946. The couple had one son.

Dom Miguel I (26 October 1802 � 14 November 1866), nicknamed The Absolutist , The Traditionalist  and The Usurper , was the King of Portugal between 1828 and 1834, the seventh child and third son of King Jo�o VI (John VI) and his queen, Carlota Joaquina of Spain.

In 1851, at the age of 48, he married Princess Adelaide of L�wenstein-Wertheim-Rosenberg, by whom he had a son and six daughters:

1. Infanta Maria das Neves of Portugal (Maria das Neves Isabel Eul�lia Carlota Adelaide Micaela Gabriela Rafaela Gonzaga de Paula de Assis In�s Sofia Romana, Infanta de Portugal) (5 August 1852 � 15 February 1941) She married  Alfonso Carlos of Bourbon, Duke of San Jaime, second son of Juan, Count of Montiz�n and his wife Archduchess Maria Beatrix of Austria-Este. Alfonso Carlos was her first cousin once removed, as Maria's father (Miguel of Portugal) and his paternal grandmother (Infanta Maria Francisca of Portugal) were siblings. Their union produced only a son who died some hours after his birth, in 1874. They were unable to have more children and died childless.

2. Miguel of Braganza (Miguel Maria Carlos Eg�dio Constantino Gabriel Rafael Gonzaga Francisco de Paula e de Assis Janu�rio de Bragan�a)(19 September 1853 � 11 October 1927) was the Miguelist claimant to the throne of Portugal from 1866 to 1920. He used the title Duke of Braganza. Miguel was first married to Princess Elisabeth of Thurn and Taxis (May 28, 1860 � February 7, 1881), the niece of Empress Elisabeth of Austria, in  1877 in Regensburg. They had three children. After the death of his first wife, he married for a second time to his first cousin Princess Maria Theresa of L�wenstein-Wertheim-Rosenberg (1870�1935). They had eight children.
2.1 Dom Miguel, Duke of Viseu (1878�1923), married Anita Stewart and had issue.
2.2 Dom Francisco Jos� of Braganza (1879�1919), died unmarried and without issue
2.3 Dona Maria Teresa of Braganza (1881�1945), married Prince Karl Ludwig of Thurn und Taxis and had issue. Karl Ludwig was a member of the Czech branch of the family (the family her mother also had belonged to).
2.4 Dona Isabel Maria of Braganza (1894�1970), married Franz Joseph, 9th Prince of Thurn and Taxis and had issue. Franz Joseph was a nephew of Miguel of Braganza 1st wife Elisabeth of Thurn and Taxis.
2.5 Dona Maria Benedita of Braganza (1896�1971), died unmarried and without issue.
2.6 Dona Mafalda of Braganza (1898�1918), died unmarried and without issue.
2.7  Dona Maria Ana of Braganza (1899�1971), married the future Karl August, 10th Prince of Thurn and Taxis and had issue. Karl August was the third son and child of Albert, 8th Prince of Thurn and Taxis, and his wife, Archduchess Margarethe Klementine of Austria. He was a younger brother of Franz Joseph, 9th Prince of Thurn and Taxis, who was married to Maria Ana�s elder sister Isabel. Of them the current Prince of Thurn and Taxis, Albert, descends.
2.8 Dona Maria Ant�nia of Braganza (1903�1973), married Sidney Ashley Chanler (son of William Astor Chanler) and had issue
2.9 Dona Filipa of Braganza (1905�1990), died unmarried and without issue
2.10 Dom Duarte Nuno, Duke of Braganza (1907�1976), married Princess Maria Francisca of Orl�ans-Braganza and had issue. Maria Francisca was a daughter of Pedro de Alc�ntara, Prince of Gr�o-Par�. The marriage was particularly popular since Maria Francisca was the great-granddaughter of Pedro II of Brazil, the younger brother of Queen Maria II. The marriage thus united the two rival lines of the Portuguese royal family.
2.11 Dona Maria Adelaide of Braganza (1912�2012), married Nicolaas van Uden and had issue