This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (April 2011)

A personal union is the combination by which two or more different states have the same monarch while their boundaries, their laws and their interests remain distinct.^[1][2] It should not be confused with a federation which is internationally considered a single state. Nor is it to be confused with dynastic union, where the union can be under a dynasty.

Personal unions can arise for very different reasons, ranging from coincidence (a princess who is already married to a king becomes queen regnant, and their child inherits the crown of both countries) to virtual annexation (where a personal union sometimes was seen as a means of preventing uprisings). 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).

Because presidents of republics are ordinarily chosen from within the citizens of the state in question, personal unions are almost entirely a phenomenon of monarchies, the unique exception in modern times being the Principality of Andorra in which one of the two co-princes is the President of France, while the other is a Roman Catholic bishop. Sometimes the term dual monarchy is used to signify a personal union between two monarchies.

There is a somewhat grey area between personal unions and federations, and the first has regularly grown into the second.

The only personal unions currently in existence are the partial union of France and Andorra, and the sixteen Commonwealth realms.

Andorra[link]

• Partial personal union with France since 1607 (the French President, and formerly the King of France, is one of the heads of state in Andorra, the other co-head of state is the Bishop of La Seu d'Urgell, Catalonia, Spain.)

Aragon, Crown of[link]

In 1162 Alfonso II of Aragon was the first person to bear the titles of King of Aragon and Count of Barcelona, ruling what was called later Crown of Aragon. James I of Aragon later created and added the Kingdom of Majorca and the Kingdom of Valencia to the Crown. Later, Charles of Ghent — Charles I of Spain, Charles V of the Holy Roman Empire— would join Aragon and Castile in a personal union that would become Spain.

Bohemia[link]

• Personal union with Poland 1003 - 1004 (Bohemia occupied by Poles)
• Personal union with Poland 1300 - 1306 and Hungary 1301 - 1305 (Wenceslas II and Wenceslas III)
• Personal union with Luxembourg 1313 - 1378 and 1383–1388
• Personal union with Hungary 1419-1439 (Sigismund of Luxemburg and his son in law) and 1490 - 1526 (Jagellon dynasty)
• Personal union with Austria and Hungary 1526 - 1918 (except years 1619 - 1620)

Brandenburg[link]

• Personal union with the Duchy of Prussia from 1618, when Albert Frederick, Duke of Prussia, died without male heirs and his son-in-law John Sigismund, Elector of Brandenburg, became ruler of both countries. Brandenburg and Prussia maintained separate governments and seats of power in Berlin and Königsberg respectively until 1701, when Frederick I consolidated them into one government.

Brazil[link]

• Personal union with Portugal, 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 also became King of Portugal for only several weeks, after which he abdicated the Portuguese throne in favour of his younger child, Princess Maria da Glória.

Commonwealth realms[link]

The conception of a personal union was suggested to keep the Irish Free State as a Commonwealth Realm.^[3]

The phrase personal union appears in some discussion about the early Commonwealth of Nations,^[4] though its application to Commonwealth was rebutted by others.^[5]

Congo Free State[link]

• Personal union with Belgium from 1885 to 1908, when the Congo Free State became a Belgian colony.

Croatia (disputed)[link]

Personal union theory[link]

According to a theory, Kingdom of Croatia^[6] and Kingdom of Hungary formed a personal union of two kingdoms in 1102, united under the Hungarian king.^{[6][7][8][9][10][11][12][13][14][15]} In c.1102, when the Croatian dynasty died out, the Croats joined the Hungarians in a personal union, but the Croatian State kept its political individuality with its ban and its assembly.^[16] King Coloman established the personal union of the Kingdom of Croatia and the Kingdom of Hungary by an agreement called Pacta conventa.^[6][15] After King Coloman was crowned as a Croatian king in Biograd, Croatian nobility retained strong powers.^[17] Although, the precise time and terms of Pacta Conventa later became a matter of dispute; nonetheless there was at least a non-written agreement that regulated the relations between Hungary and Croatia in approximately the same way.^[18]

In the union with Hungary, institutions of separate Croatian statehood were maintained through the Sabor (an assembly of Croatian nobles) and the ban (viceroy). In addition, the Croatian nobles retained their lands and titles.^[6][19] Coloman retained the institution of the Sabor and relieved the Croatians of taxes on their land.^[6] Coloman's successors continued to crown themselves as Kings of Croatia separately in Biograd na Moru until the time of Bela IV.^[20] In the 14th century a new term arose to describe the collection of de jure independent states under the rule of the Hungarian King: Archiregnum Hungaricum (Lands of the Crown of Saint Stephen).^{[unreliable source?][21]}

Medieval Hungary and Croatia were (in terms of public international law) allied by means of personal union until the Battle of Mohács in 1526.^{[citation needed]} On January 1, 1527, the Croatian nobles at Cetin unanimously elected Ferdinand, Archduke of Austria, as their king, and confirmed the succession to him and his heirs.^[22] However, officially the Hungarian-Croatian state existed until the beginning of the 20th century and the Treaty of Trianon.^[13][14][15]

Hungarian occupation theory[link]

According to another theory, Croatia was subjugated and incorporated into Hungary.^[23] The alleged document of the personal union, the so-called Pacta Conventa is most likely a forgery from centuries later.^{[17][20][24][25][26][27][28]}

Matjaž Klemenčič and Mitja Žagar claim that the Pacta Conventa, the alleged document under which Croatians became vassals of Hungarians never existed, but the story about it was important for the Croatian position in the Habsburg Empire during the eighteenth and nineteenth centuries, when the Croats claimed their right for statehood on the basis of that agreement.^[17] Although Croatia ceased to exist as an independent state when King Coloman of Hungary defeated the last Croatian king, the Croatian nobility retained some powers.^[17]

According to the Federal Research Division of the Library of Congress, the Croats enjoyed their own medieval kingdom for several centuries before a long period of Hungarian rule from 1102 to 1918.^[29] Most Croats lived under Hungarian kings until 1526 and under Habsburg monarchs thereafter;^[29] the Croats of Bosnia and Hercegovina and Slavonia lived under Ottoman rule for several hundred years; and the Croats of Dalmatia passed from Hungarian to Venetian to Austrian rule.^[29] With the help of Roman Catholic clerics, the Croats maintained a strong collective memory of their former statehood despite their centuries of foreign domination.^[29]

Analysis, conclusion[link]

The actual nature of the relationship is inexplicable in modern terms because it varied from time to time.^[30] Sometimes Croatia acted as an independent agent and at other times as a vassal of Hungary.^[30] However, Croatia retained a large degree of internal independence.^[30] The degree of Croatian autonomy fluctuated throughout the centuries as did its borders.^[31]

Denmark[link]

• Sweyn Forkbeard ruled both Denmark and England from 1013 to 1014. He also ruled Norway from 999 to 1014.
• Cnut the Great ruled both Denmark and England from 1018 to 1035. He also ruled Norway 1028 to 1035.
• Harthacanute ruled both Denmark and England from 1040 to 1042.
• Personal union with Norway 1042-1047 under the Norwegian king Magnus I.
• Personal union with Norway from 1380 to 1814 (the Norwegian Riksråd was abolished in 1536).
• The Kalmar Union with Norway and Sweden from 1389/97 to 1521/23 (sometimes defunct).^[vague]
• The kings of Denmark at the same time being dukes of Schleswig and Holstein 1460-1864 (Holstein being part of the Holy Roman Empire, now part of Germany).
• Personal union with Iceland from 1918 to 1944 when Iceland became a republic.