The Royals Really Are All Related. The most recent common ancestors of all current and former European monarchs.

 

The most recent common ancestors MRCA of hereditary European monarchs.  The Royals Really Are All Related, https://youtu.be/fjSdN3RuopI.
 

The most recent common ancestor (MRCA) of any set of organisms is the most recent individual from which all organisms in the group are directly descended. The term is most frequently used by humans. The MRCA of a set of individuals can sometimes be determined by referring to an established pedigree.
 

The royal descendants of John William Friso, Prince of Orange currently occupy all the hereditary European royal thrones. Friso and his wife, Landgravine Marie Louise of Hesse-Kassel, are the most recent common ancestors of all European monarchs, current and former, that have reigned since World War II.

While some of the current European monarchs are related to each other within a few generations, we have to go back a few hundred years to find the ancestors that all of them have in common: Johan Willem Friso of Orange-Nassau, Prince of Orange 14 August 1687 – 14 July 1711. He and his wife Landgravine Marie Louise of Hesse-Kassel (7 February 1688 – 9 April 1765), had two children, Princess Amalia and Willem IV, Prince of Orange. It is through these two children that all the current reigning monarchs of Europe descend.
 

Johan Willem Friso was the son of Henry Casimir II, Prince of Nassau-Dietz, and Princess Henriëtte Amalia of Anhalt-Dessau who was both first cousins of William III. As such, he was a member of the House of Nassau (the branch of Nassau-Dietz), and through the testamentary dispositions of William III became the progenitor of the new line of the House of Orange-Nassau. He was educated under Jean Lemonon, a professor at the University of Franeker.
 

Charles I, Landgrave of Hesse-Kassel, by his wife and cousin, Princess Maria Amalia of Courland. Two of her siblings included King Frederick I of Sweden and William VIII, Landgrave of Hesse-Kassel.
 

Between 9 April 1939 and 18 May 1941 and again between 31 July 1943 and 8 September 2022 John William Friso and Maria Louise were the most recent common ancestors to all reigning European monarchs. Between 18 May 1941 and 31 July 1943, the puppet Independent State of Croatia was a kingdom under Prince Aimone, Duke of Aosta (his regnal name was Tomislav II) in opposition to the exiled monarchy under Peter II of Yugoslavia. Peter and Aimone's wife Irene descended from John William Friso and Marie Louise, but not Aimone himself, so the position of royal MRCA was held by John Frederick, Margrave of Brandenburg-Ansbach (1654 – 1686), who held the distinction alone since the descents came from both his marriages.

Before 9 April 1939 King Zog I of Albania makes the position of MRCA unknown since his ancestry is itself almost entirely unknown and he has no traceable connection to other European royalty except through his wife Geraldine.

Since the death of Elizabeth II on 8 September 2022, the MRCA of hereditary European monarchs is John Frederick's great-grandson Louis IX, Landgrave of Hesse-Darmstadt (1719 – 1790), and his wife Caroline of Zweibrücken (1721 – 1774), who were formerly common ancestors to all reigning European monarchs except Elizabeth II. This is because Charles III is descended through his paternal grandmother from Louis IX's grandson Louis II, Grand Duke of Hesse via both her parents. Despite this, John William Friso and Marie Louise remain to be the most recent common ancestor of all current and former European monarchs.
 

When William, prince of Orange died, the throne of England, Scotland, Wales, and Ireland went to his wife's sister queen Anne, before she created the basis for the succession laws used today, and then her cousin George 1st was chosen as the next monarch, as he was the most senior Protestant in the family.

San Jose Costa Rica, December 22, 2022, Rafael A. Vilagut-Vega, alberto.doer@gmail.com.
 

Related episode, "A new ebook, The Lineage of the Portuguese Conquerors of the 16th century" by Rafael Alberto Vilagut. December 10, 2022, blog Happy and Healthy (Feliz y Saludable), http://felizysaludable.blogspot.com/2022/12/a-new-ebook-lineage-of-portuguese.html.