A personal union is a combination of two or more
monarchicalstates 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:
decolonization, where ex-colonies install the monarch of the former colonizing power as their own upon becoming independent, e.g. several former members of the
British Empire (then becoming
Commonwealth realms)
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.
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.
Americas
Brazil
Personal union with Portugal, under
Pedro I of Brazil (Pedro IV of Portugal), from 10 March to 28 May 1826. Pedro was the
Prince Royal of Portugal, Brazil and the Algarves when he declared the independence of Brazil in 1822, becoming its first emperor. When his father (
John VI of Portugal) died, Pedro also became King of Portugal, but abdicated the Portuguese throne 79 days later in favour of his older child
Princess Maria da Glória.
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:
First and
Second French Empires (1806–1814, 1815–1815 and 1852–1870).
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.
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.
Personal union, as
Irish Free State (1922–1937) then as
Éire (1937–1949), with the United Kingdom of Great Britain and Northern Ireland. (The period 1937–1949
is disputed).
Personal union with
Bohemia, 1313–1378 and 1383–1388.
Personal union with the Netherlands from 1815 to 1890, when
King and Grand Duke William III died leaving only a daughter,
Wilhelmina. Since Luxembourg held to
Salic Law, Wilhelmina's distant cousin
Adolphe succeeded to the Grand Duchy, ending the personal union.
Naples
Personal union with
Kingdom of Hungary from 1385 to 1386 under the rule of Charles II of Hungary.
Personal union with
Crown of Aragon (1442–1458 and 1504–1516).
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.
Personal union with Brazil, under
Peter I of Brazil (Peter IV of Portugal), from 10 March 1826 to 28 May 1826. Peter was the
Prince Royal of Portugal, Brazil and the Algarves when he declared the independence of Brazil in 1822, becoming its first emperor. When his father (
John VI of Portugal) died, Peter became also king of Portugal for only a few weeks, after which he abdicated the Portuguese throne in favor of his older daughter,
Princess Maria da Glória.
Personal union between
Kingdom of Prussia and
Principality of Neuchâtel, 1707–1806 and 1814–1848. The King of Prussia exchanged territories with France during the 1806–1814 interim.
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.
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.
Personal union, as Kingdom of Scotland, with the
Kingdom of England and
Kingdom of Ireland (1603–1707) following the accession of
James VI, King of Scots, to the joint English and Irish throne. (All monarchs of Scotland were in a personal union with England and Ireland throughout the period 1603–1707, with the exception of
Charles II, reigning solely as King of Scots 1649–1651, and the subsequent
interregnum between 1651 and restoration of the
House of Stuart in 1660)1
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:
Uniquely, the
President of France is ex officio a constitutional monarch (or, more accurately,
diarch) in neighboring
Andorra, with the title of
Co-Prince. This status was inherited from the role of the French monarchs in Andorra.
During the later stages of the
Spanish American Wars of Independence,
Simón Bolívar was simultaneously President of
Gran Colombia (24 February 1819 - 4 May 1830), President of
Peru (10 February 1824 – 28 January 1827), and President of
Bolivia (12 August 1825 - 29 December 1825). Bolívar had, as President and military Commander-in-Chief of Colombia, led a Colombian army to secure Peruvian independence in 1824-25, and was given the office of President by the Patriot republican governments of both Peru and Bolivia (renamed in his honor from "Upper Peru") as an emergency measure to help secure independence from Spain. After the end of the war, Bolívar relinquished his Peruvian and Bolivian offices and returned to Colombia.
Srodecki, Paul; Kersken, Norbert; Petrauskas, Rimvydas, eds. (2023). Unions and Divisions: New Forms of Rule in Medieval and Renaissance Europe (First ed.). London and New York, NY:
Routledge.
ISBN978-1-032-05750-7.