Personal union

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A personal union is a combination of two or more states that have the same monarch while their boundaries, laws, and interests remain distinct. [1] A real union, by contrast, involves the constituent states being to some extent interlinked, such as by sharing some limited governmental institutions. Unlike a personal union, in a federation or a unitary state, a central (federal) government spanning all member states exists, with the degree of self-governance distinguishing the two. The ruler in a personal union does not need to be a hereditary monarch. [note 1]


The term was coined by German jurist Johann Stephan Pütter, introducing it into Elementa iuris publici germanici (Elements of German Public Law) of 1760. [2]

Personal unions can arise for several reasons, such as:

They can also be codified (i.e., the constitutions of the states clearly express that they shall share the same person as head of state) or non-codified, in which case they can easily be broken (e.g., by the death of the monarch when the two states have different succession laws).

The concept of a personal union has only very rarely crossed over from monarchies into republics.

There are currently two personal unions in the world: the Commonwealth realms, who share Charles III as their head of state, and one of the Co-Princes of Andorra being the President of France.

Monarchies in personal union


Congo Free State and Belgium

  • Personal union with Belgium from 1885 to 1908, when the Congo Free State became a Belgian colony. The only sovereign during this period was Leopold II, who continued as king of Belgium until his death a year later in 1909.





  • Personal union with Shenyang in the Mongol-led Yuan dynasty of China (1308–1313; King Chungseon)
    • As King of Goryeo (高麗國王) and King of Shenyang (瀋陽王) in 1308–1310
    • As King of Goryeo and King of Shen (瀋王) in 1310–1313

King Chungseon reigned as King of Goryeo in 1298 and 1308–1313 and as King of Shenyang or King of Shen from 1307 (according to the History of Yuan ) or 1308 (according to Goryeosa ) to 1316. At that time, Goryeo had already become a vassal of Yuan dynasty and the Yuan imperial family and the Goryeo royal family had close relationship by marriages of convenience. Because he was a very powerful man during Emperor Wuzong's reign, he could become the King of Shenyang where many Korean people lived in China. However, he lost his power in the Yuan imperial court after the death of the Emperor Wuzong. Because the Yuan dynasty made Chungseon abdicate the crown of the Goryeo in 1313, the personal union was ended. King Chungsuk, Chungseon's eldest son, became the new King of Goryeo. In 1316, the Yuan dynasty made Chungseon abdicate the crown of Shen in favour of Wang Go, one of his nephews, resulting in him becoming the new King of Shen.




Due to Andorra's special government form resulting from the Paréage of 1278, it is a diarchy with co-princes. One of them is the Bishop of Urgell, the other was originally the Count of Foix. It is through this feudal co-prince that the Principality has entered partial personal union with:

In 1607 the feudal co-prince was Henry IV of France, who issued an edict that his position should be held by the French Head of State. While during the French Revolution, the new government did not take up the title, all versions of France since 1806 regardless of their government form have accepted that their head of state is an ex officio co-prince. This led to personal unions with:







1: After 1707, see Great Britain below.


Note: The point at issue in the War of the Spanish Succession was the fear that the succession to the Spanish throne dictated by Spanish law, which would devolve on Louis, le Grand Dauphin already heir to the throne of France would create a personal union that would upset the European balance of power; France had the most powerful military in Europe at the time, and Spain the largest empire.


Great Britain

Before 1707, see England and Scotland.

After 1801, see United Kingdom below.


Holy Roman Empire


  • Personal union with Croatia 1102–1918 (see § Croatia above for details).
  • Personal union with Poland and Bohemia 1301–1305.
  • Personal union with Poland from 1370 to 1382 under the reign of Louis the Great. This period in Polish history is sometimes known as the Andegawen Poland . Louis inherited the Polish throne from his maternal uncle Casimir III. After Louis' death the Polish nobles (the szlachta ) decided to end the personal union, since they did not want to be governed from Hungary, and chose Louis' younger daughter Jadwiga as their new ruler, while Hungary was inherited by his elder daughter Mary. Personal union with Poland for the second time from 1440 to 1444.
  • Personal union with Naples from 1385 to 1386 under the reign of Charles III of Naples.
  • Personal union with Bohemia, 1419–1439 (with both in interregnum during 1437–1438), 1453–1457 and 1490–1918.
  • Personal union with the Archduchy of Austria, 1437–1439, 1444–1457, and 1526–1806.
  • Personal union with the Holy Roman Empire, 1410–1439, 1556–1608, 1612–1740 and 1780–1806.
  • Real union with Austria, 1867–1918 (the dual monarchy of Austria-Hungary) under the reigns of Franz Joseph and Charles IV.







  • Personal union with France from 1285 to 1328 due to the marriage between Philip IV of France and Joan I of Navarre and the reign of their three sons, and from 1589 to 1620 due to the accession of Henry IV, after which Navarre was formally integrated into France.



  • Sweyn Forkbeard ruled both Norway and Denmark from 999 to 1014. He also ruled England from 1013 to 1014.
  • Cnut the Great ruled both England and Denmark from 1018 to 1035. He also ruled Norway from 1028 to 1035.
  • Personal union with Denmark 1042–1047. Magnus I of Norway, who died of unclear circumstances, ruled both Norway and Denmark.
  • Personal union with Sweden from 1319 to 1343.
  • Personal union with Sweden from 1449 to 1450.
  • Personal union with Denmark from 1380 to 1389/97.
  • The Kalmar Union with Denmark and Sweden from 1389/97 to 1521/23 (sometimes defunct).[ vague ]
  • Personal union with Denmark 1523 to 1814.
  • Personal union with Sweden from 1814 (when Norway declared independence from Denmark and was forced into a union with Sweden) to 1905.








Saxe-Coburg and Saxe-Gotha

In 1826, the newly created Duchy of Saxe-Coburg and Gotha was initially a double duchy, ruled by Duke Ernest I in a personal union. In 1852, the duchies were bound in a political and real union. They were then a quasi-federal unitary state, even though later attempts to merge the duchies failed.

Saxe-Weimar and Saxe-Eisenach

The duchies of Saxe-Weimar and Saxe-Eisenach were in personal union from 1741, when the ruling house of Saxe-Eisenach died out, until 1809, when they were merged into the single duchy of Saxe-Weimar-Eisenach.

Schleswig and Holstein

Duchies with peculiar rules for succession. See the Schleswig-Holstein Question.

The kings of Denmark at the same time being dukes of Schleswig and Holstein 1460–1864. (Holstein being part of the Holy Roman Empire, while Schleswig was a part of Denmark). The situation was complicated by the fact that for some time, the Duchies were divided among collateral branches of the House of Oldenburg (the ruling House in Denmark and Schleswig-Holstein). Besides the "main" Duchy of Schleswig-Holstein-Glückstadt, ruled by the Kings of Denmark, there were states encompassing territory in both Duchies. Notably the Dukes of Schleswig-Holstein-Gottorp and the subordinate Dukes of Schleswig-Holstein-Beck, Schleswig-Holstein-Sonderburg-Augustenburg and Schleswig-Holstein-Sonderburg-Glücksburg.

Schwarzburg-Rudolstadt and Schwarzburg-Sondershausen

The duchies of Schwarzburg-Rudolstadt and Schwarzburg-Sondershausen were in personal union from 1909, when Prince Günther of Schwarzburg-Rudolstadt succeeded also to the throne of Schwarzburg-Sondershausen, until 1918, when he (and all the other German monarchs) abdicated.


1: After 1707, see Great Britain above. After 1801, see United Kingdom below.


Leon, Castile and Aragon



United Kingdom


After 1542, see England above.

Republics in personal union

Because heads of state and government of republics are ordinarily chosen from within the citizens of the state in question, sovereign republics very rarely share common leaders. A few examples are:

See also


  1. In the Holy Roman Empire, many prince-bishops had themselves elected to separate prince-bishoprics, which they ruled in a personal union. For example, Joseph Clemens of Bavaria (1671–1723) was Prince-Bishop of Freising (1685–1694), Prince-Bishop of Regensburg (1685–1694), Prince-Elector of Cologne (1688–1723), Prince-Bishop of Liège (1694–1723) and Prince-Bishop of Hildesheim (1702–1723).

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