The monarchs of Prussia were members of the

House of Hohenzollern The House of Hohenzollern (, ; , ; ) is a formerly royal (and from 1871 to 1918, imperial) German dynasty whose members were variously princes, Prince-elector, electors, kings and emperors of Hohenzollern Castle, Hohenzollern, Margraviate of Bran ...

who were the hereditary rulers of the former German state of

Prussia Prussia (; ; Old Prussian: ''Prūsija'') was a Germans, German state centred on the North European Plain that originated from the 1525 secularization of the Prussia (region), Prussian part of the State of the Teutonic Order. For centuries, ...

from its founding in 1525 as the

Duchy of Prussia The Duchy of Prussia (, , ) or Ducal Prussia (; ) was a duchy in the region of Prussia established as a result of secularization of the Monastic Prussia, the territory that remained under the control of the State of the Teutonic Order until t ...

. The Duchy had evolved out of the

Teutonic Order The Teutonic Order is a religious order (Catholic), Catholic religious institution founded as a military order (religious society), military society in Acre, Israel, Acre, Kingdom of Jerusalem. The Order of Brothers of the German House of Sa ...

, a

Roman Catholic The Catholic Church (), also known as the Roman Catholic Church, is the largest Christian church, with 1.27 to 1.41 billion baptized Catholics worldwide as of 2025. It is among the world's oldest and largest international institut ...

crusader state The Crusader states, or Outremer, were four Catholic polities established in the Levant region and southeastern Anatolia from 1098 to 1291. Following the principles of feudalism, the foundation for these polities was laid by the First Crusade ...

and

theocracy Theocracy is a form of autocracy or oligarchy in which one or more deity, deities are recognized as supreme ruling authorities, giving divine guidance to human intermediaries, with executive and legislative power, who manage the government's ...

located along the eastern coast of the

Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by the countries of Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden, and the North European Plain, North and Central European Plain regions. It is the ...

. The Teutonic Knights were under the leadership of a Grand Master, the last of whom, Albert, converted to

Protestantism Protestantism is a branch of Christianity that emphasizes Justification (theology), justification of sinners Sola fide, through faith alone, the teaching that Salvation in Christianity, salvation comes by unmerited Grace in Christianity, divin ...

and secularized the lands, which then became the

. The Duchy was initially a vassal of the

Kingdom of Poland The Kingdom of Poland (; Latin: ''Regnum Poloniae'') was a monarchy in Central Europe during the Middle Ages, medieval period from 1025 until 1385. Background The West Slavs, West Slavic tribe of Polans (western), Polans who lived in what i ...

, as a result of the terms of the

Prussian Homage The Prussian Homage or Prussian Tribute (; ) was the formal investiture of Albert, Duke of Prussia ( 1490-1568), with his Duchy of Prussia as a fief of the Kingdom of Poland that took place on 10 April 1525 in the then capital of Kraków, Kin ...

whereby Albert was granted the Duchy as part of the terms of peace following the Prussian War. When the main line of Prussian Hohenzollerns died out in 1618, the Duchy passed to a different branch of the family, who also reigned as Electors of Brandenburg in the

Holy Roman Empire The Holy Roman Empire, also known as the Holy Roman Empire of the German Nation after 1512, was a polity in Central and Western Europe, usually headed by the Holy Roman Emperor. It developed in the Early Middle Ages, and lasted for a millennium ...

. While still nominally two different territories,

under the suzerainty of

Poland Poland, officially the Republic of Poland, is a country in Central Europe. It extends from the Baltic Sea in the north to the Sudetes and Carpathian Mountains in the south, bordered by Lithuania and Russia to the northeast, Belarus and Ukrai ...

and

Brandenburg Brandenburg, officially the State of Brandenburg, is a States of Germany, state in northeastern Germany. Brandenburg borders Poland and the states of Berlin, Mecklenburg-Vorpommern, Lower Saxony, Saxony-Anhalt, and Saxony. It is the List of Ger ...

under the suzerainty of the

, the two states are known together historiographically as Brandenburg-Prussia. Following the

third Northern War In the Great Northern War (1700–1721) a coalition led by the Tsardom of Russia successfully contested the supremacy of the Swedish Empire in Northern, Central and Eastern Europe. The initial leaders of the anti-Swedish alliance were Peter ...

, a series of treaties freed the

from vassalage to any other state, making it a fully sovereign Duchy in its own right. This complex situation (where the

Hohenzollern The House of Hohenzollern (, ; , ; ) is a formerly royal (and from 1871 to 1918, imperial) German dynasty whose members were variously princes, electors, kings and emperors of Hohenzollern, Brandenburg, Prussia, the German Empire, and Romania. ...

ruler of the independent Duchy of Prussia was also a subject of the

Holy Roman Emperor The Holy Roman Emperor, originally and officially the Emperor of the Romans (disambiguation), Emperor of the Romans (; ) during the Middle Ages, and also known as the Roman-German Emperor since the early modern period (; ), was the ruler and h ...

Elector of Brandenburg This article lists the Margraves and Prince-elector, Electors of Margraviate of Brandenburg, Brandenburg during the time when Brandenburg was a constituent state of the Holy Roman Empire. The Mark, or ''March'', of Brandenburg was one of the prima ...

) laid the eventual groundwork for the establishment of the

Kingdom of Prussia The Kingdom of Prussia (, ) was a German state that existed from 1701 to 1918.Marriott, J. A. R., and Charles Grant Robertson. ''The Evolution of Prussia, the Making of an Empire''. Rev. ed. Oxford: Clarendon Press, 1946. It played a signif ...

in 1701. For diplomatic reasons, the rulers of

called themselves

King in Prussia King ''in'' Prussia (German language, German: ''König in Preußen'') was a title used by the Prussian kings (also in personal union Elector of Brandenburg, Electors of Brandenburg) from 1701 to 1772. Subsequently, they used the title King ''of' ...

from 1701 to 1772. They still nominally owed fealty to the Emperor as Electors of Brandenburg, so the "King in Prussia" title (as opposed to "King of Prussia") avoided offending the Emperor. Additionally, calling themselves "King ''of'' Prussia" implied sovereignty over the entire Prussian region, parts of which were still part of

. As the Prussian state grew through several wars and diplomatic moves throughout the 18th century, it became apparent that

had become a Great Power in its own right. By 1772, the pretense was dropped, and the style "King of Prussia" was adopted. The Prussian kings continued to use the title "Elector of Brandenburg" until the end of the Holy Roman Empire in 1806, reflecting the

legal fiction A legal fiction is a construct used in the law where a thing is taken to be true, which is not in fact true, in order to achieve an outcome. Legal fictions can be employed by the courts or found in legislation. Legal fictions are different from ...

that their domains within the empire were still under the ultimate overlordship of the Emperor. Legally, the Hohenzollerns ruled Brandenburg in

personal union A personal union is a combination of two or more monarchical states that have the same monarch while their boundaries, laws, and interests remain distinct. A real union, by contrast, involves the constituent states being to some extent in ...

with their Prussian kingdom, but in practice they treated their domains as a single unit. The Hohenzollerns gained ''de jure'' sovereignty over Brandenburg when the empire dissolved in 1806, and Brandenburg was formally merged into Prussia. In 1871, in the aftermath of the

Franco-Prussian War The Franco-Prussian War or Franco-German War, often referred to in France as the War of 1870, was a conflict between the Second French Empire and the North German Confederation led by the Kingdom of Prussia. Lasting from 19 July 1870 to 28 Janua ...

, the

German Empire The German Empire (),; ; World Book, Inc. ''The World Book dictionary, Volume 1''. World Book, Inc., 2003. p. 572. States that Deutsches Reich translates as "German Realm" and was a former official name of Germany. also referred to as Imperia ...

was formed, and the King of Prussia,

Wilhelm I Wilhelm I (Wilhelm Friedrich Ludwig; 22 March 1797 – 9 March 1888) was King of Prussia from 1861 and German Emperor from 1871 until his death in 1888. A member of the House of Hohenzollern, he was the first head of state of a united Germany. ...

was crowned

German Emperor The German Emperor (, ) was the official title of the head of state and Hereditary monarchy, hereditary ruler of the German Empire. A specifically chosen term, it was introduced with the 1 January 1871 constitution and lasted until the abdicati ...

. From that point forward, though the Kingdom of Prussia retained its status as a constituent state of the empire (by far the largest and most powerful), all subsequent Kings of Prussia also served as German Emperor, and that title took precedence.

Duchy of Prussia (1525–1701)

Kingdom of Prussia (1701–1918)

Timeline

Pretenders to the Prussian throne since 1918

* William II (9 November 1918 – 4 June 1941) *

Frederick William The name Frederick William usually refers to several monarchs and princes of the Hohenzollern dynasty: * Frederick William, Elector of Brandenburg (1620–1688) * Frederick William, Duke of Mecklenburg-Schwerin (1675–1713) * Frederick William I of ...

(4 June 1941 – 20 July 1951) * Louis Ferdinand (20 July 1951 – 26 September 1994) * George Frederick (26 September 1994 – ''present'')

Family tree

References

Bibliography

* . *

External links

House of Hohenzollern
{{Orders and decorations of the Kingdom of Prussia *

Dukes of Prussia

Monarchs A monarch () is a head of stateWebster's II New College Dictionary. "Monarch". Houghton Mifflin. Boston. 2001. p. 707. for life or until abdication, and therefore the head of state of a monarchy. A monarch may exercise the highest authority an ...