William I (Wilhelm Friedrich Ludwig; 22 March 1797 – 9 March 1888), or Wilhelm I, 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. He was de facto head of state of Prussia from 1858, when he became regent for his brother Frederick William IV. During the reign of his grandson Wilhelm II, he was known as Wilhelm the Great.

The second son of Prince Frederick William and Louise of Mecklenburg-Strelitz, William was not expected to ascend to the throne. His grandfather, King Frederick William II died the year he was born, and his father was crowned Frederick William III. William fought with distinction during the War of the Sixth Coalition, and afterwards became a prominent figure within the Prussian Army. In 1840, his childless elder brother became King of Prussia, making him heir presumptive. William played a major role in crushing the Revolutions of 1848 in Germany, although he was briefly forced into exile in England. Frederick William IV suffered a stroke in 1857 and was left incapacitated, and William was formally named Prince Regent a year later. In 1861, William ascended to the Prussian throne on his elder brother's death.

Upon ascension, William immediately came into conflict with the liberal Landtag over his proposed military budget. In response, he appointed Otto von Bismarck to the post of Minister President in order to force through his proposals, beginning a partnership that would last for the rest of his life. On the foreign front, William oversaw Prussian victories in the Second Schleswig War and the Austro-Prussian War, establishing Prussia as the leading German power. In 1871, through Bismarck's maneuvers, the unification of Germany was achieved following the Franco-Prussian War. The German Empire was proclaimed and William was granted the title of German Emperor. Even though he had considerable power as Kaiser, William largely left the affairs of the state to Bismarck. Later in life he was the target of multiple failed assassination attempts, which enabled Bismarck to push through a series of anti-socialist laws. In 1888, which came to be known as the Year of the Three Emperors, William died at the age of 90 after a short illness and was succeeded by his son Frederick. Frederick, already suffering from cancer, died 99 days later and the throne passed to Wilhelm II.

The future king and emperor was born William Frederick Louis of Prussia (Wilhelm Friedrich Ludwig von Preußen) in the Kronprinzenpalais in Berlin on 22 March 1797. As the second son of Louise of Mecklenburg-Strelitz and Prince Frederick William, himself son of King Frederick William II, William was not expected to ascend to the throne. His grandfather died the year he was born, at age 53, in 1797, and his father Frederick William III became king. He was educated from 1801 to 1809 by Johann Friedrich Gottlieb Delbrück [de], who was also in charge of the education of William's brother, the Crown Prince Frederick William. At age twelve, his father appointed him an officer in the Prussian army.

William served in the army from 1814 onward. Like his father, he fought against Napoleon I of France during the part of the Napoleonic Wars known in Germany as the Befreiungskriege ("Wars of Liberation", otherwise known as the War of the Sixth Coalition), and was reportedly a very brave soldier. He was made a captain (Hauptmann) and won the Iron Cross for his actions at Bar-sur-Aube. The war and the fight against France left a lifelong impression on him, and he had a long-standing antipathy towards the French.

In 1815, William was promoted to major and commanded a battalion of the 1. Garderegiment. He fought under Gebhard Leberecht von Blücher at the Battles of Ligny and Waterloo. In 1817, he accompanied his sister Charlotte to Saint Petersburg, when she married Emperor Nicholas I of Russia, becoming Empress Alexandra Feodorovna.

In 1816, William became the commander of the Stettiner Gardelandwehrbataillon and in 1818 was promoted to Generalmajor. The next year, William was appointed inspector of the VII. and VIII. Army Corps. This made him a spokesman of the Prussian Army within the House of Hohenzollern. He argued in favour of a strong, well-trained, and well-equipped army. In 1820, William became commander of the 1. Gardedivision and in 1825 was promoted to commanding general of the III. Army Corps.

Around this time, William became romantically linked with his cousin, Polish noblewoman Elisa Radziwill. In 1826, William was forced to break off the relationship by his father, who deemed it an inappropriate match. It is alleged that Elisa had an illegitimate daughter by William who was brought up by Joseph and Caroline Kroll, owners of the Kroll Opera House in Berlin, and was given the name Agnes Kroll. She married a Carl Friedrich Ludwig Dettman (known as "Louis") and emigrated to Sydney, in 1849. They had a family of three sons and two daughters. Agnes died in 1904.

In 1829, William married Princess Augusta, the daughter of Grand Duke Karl Friedrich of Saxe-Weimar-Eisenach and Maria Pavlovna, the sister of Nicholas I. Their marriage was outwardly stable, but not a very happy one. In 1834-37 he had the Old Palace in Berlin built as a new family home, in which he continued to live later as king and emperor, while he only used the Berlin Palace for representative purposes.

On 7 June 1840 his older brother became King of Prussia. Since he had no children, William was first in line to succeed him to the throne and thus was given the title Prinz von Preußen. Against his convictions but out of loyalty towards his brother, William signed the bill setting up a Prussian parliament in 1847 and took a seat in the upper chamber, the Prussian House of Lords.

During the Revolutions of 1848, William successfully crushed a revolt in Berlin that was aimed at Frederick William IV. The use of cannons made him unpopular at the time and earned him the nickname Kartätschenprinz (Prince of Grapeshot). Indeed, he had to flee to England for a while, disguised as a merchant. He returned and helped to put down an uprising in Baden, where he commanded the Prussian army. In October 1849, he became governor-general of the Rhine Province and Province of Westphalia, with a seat at the Electoral Palace, Koblenz.

During their time at Koblenz, William and his wife entertained liberal scholars such as the historian Maximilian Wolfgang Duncker, August von Bethmann-Hollweg and Clemens Theodor Perthes [de]. William's opposition to liberal ideas gradually softened.

In 1854, the prince was raised to the rank of a field-marshal and made governor of the federal Fortress of Mainz. In 1857 Frederick William IV suffered a stroke and became mentally disabled for the rest of his life. In January 1858, William became Prince Regent for his brother, initially only temporarily but after October on a permanent basis. Against the advice of his brother, William swore an oath of office on the Prussian constitution and promised to preserve it "solid and inviolable". William appointed a liberal, Karl Anton von Hohenzollern-Sigmaringen, as Minister President and thus initiated what became known as the "New Era" in Prussia, although there were conflicts between William and the liberal majority in the Landtag on matters of reforming the armed forces.

On 2 January 1861, Frederick William IV died and William ascended the throne as William I of Prussia. In July, a student from Leipzig attempted to assassinate William, but he was only lightly injured. Like Frederick I of Prussia, William travelled to Königsberg and there crowned himself at the Schlosskirche. William chose the anniversary of the Battle of Leipzig, 18 October, for this event, which was the first Prussian coronation ceremony since 1701 and the only coronation of a German king after 1806. William refused to comply with his brother's wish, expressed in Frederick William's last will, that he should abrogate the constitution.

William inherited a conflict between Frederick William and the liberal Landtag. He was considered to be politically neutral as he intervened less in politics than his brother. In 1862 the Landtag refused an increase in the military budget needed to pay for the already implemented reform of the army. This involved expanding the peacetime army from 150,000 to 200,000 men and the annual number of new recruits from 40,000 to 63,000. However, the truly controversial part was keeping the length of military service (raised in 1856 from two years) at three years. When his request (backed by his Minister of War Albrecht von Roon) was refused, William first considered abdicating, but his son, the Crown Prince, advised strongly against it. Then, on the advice of Roon, William appointed Otto von Bismarck as Minister President in order to force through the proposals. Under the Prussian constitution, the Minister President was responsible solely to the king, not to the Landtag. Bismarck, a conservative Prussian Junker and loyal friend of the king, liked to see his working relationship with William as that of a vassal to his feudal superior. Nonetheless, it was Bismarck who effectively directed affairs, domestic as well as foreign; on several occasions he gained William's assent by threatening to resign.

During his reign, William was the commander-in-chief of the Prussian forces in the Second Schleswig War against Denmark in 1864 and the Austro-Prussian War in 1866. After the latter was won by Prussia, William wanted to march on to Vienna and annex Austria, but was dissuaded from doing so by Bismarck and his son Crown Prince Frederick. Bismarck wanted to end the war quickly, so as to allow Prussia to ally with Austria if it needed to at a later date; Frederick was also appalled by the casualties and wanted a speedy end to hostilities. During a heated discussion, Bismarck threatened to resign if William continued to Vienna; Bismarck got his way. William had to content himself with becoming the de facto ruler of the northern two-thirds of Germany. Prussia annexed several of Austria's allies north of the Main, as well as Schleswig-Holstein. Saxe-Lauenburg was already in a personal union with Prussia since 1865 (which became a full union in 1876).

In 1867, the North German Confederation was created as a federation (federally organised state) of the North German and Central German states under the permanent presidency of Prussia. William assumed the Bundespräsidium, the presidium of the Confederation; the post was a hereditary office of the Prussian crown. Not expressis verbis, but in function he was the head of state. Bismarck intentionally avoided a title such as Präsident as it sounded too republican. William became also the constitutional Bundesfeldherr, the commander of all federal armed forces. Via secret treaties with the South German states, he also became commander of their armies in times of war. In 1870, during the Franco-Prussian War, William was in command of all the German forces at the crucial Battle of Sedan.

During the Franco-Prussian War, the South German states joined the North German Confederation, which was reorganized as the German Empire (Deutsches Reich). The title of Bundespräsidium was replaced with the title of German Emperor (Deutscher Kaiser). This was decided on by the legislative organs, the Reichstag and Bundesrat, and William agreed to this on 8 December in the presence of a Reichstag delegation. The new constitution and the title of Emperor came into effect on 1 January 1871.

William, however, hesitated to accept the constitutional title, as he feared that it would overshadow his own title as King of Prussia. He also wanted it to be Kaiser von Deutschland ("Emperor of Germany"), but Bismarck warned him that the South German princes and the Emperor of Austria might protest. William eventually—though grudgingly—relented and on 18 January, he was formally proclaimed as emperor in the Hall of Mirrors in the Palace of Versailles. The date was chosen as the coronation date of the first Prussian king in 1701. In the national memory, 18 January became the day of the foundation of the Empire (Reichsgründungstag), although it did not have a constitutional significance.

To many intellectuals, the coronation of William was associated with the restoration of the Holy Roman Empire. Felix Dahn wrote a poem, "Macte senex Imperator" ('Hail thee, old emperor') in which he nicknamed William Barbablanca (whitebeard), a play on the name of the medieval emperor Frederick Barbarossa (redbeard). According to the King asleep in mountain legend, Barbarossa slept under the Kyffhäuser mountain until Germany had need of him. William I was thus portrayed as a second coming of Barbarossa. The Kyffhäuser Monument portrays both emperors.

In 1872, he arbitrated a boundary dispute between the United Kingdom and the United States, deciding in favor of the U.S. and placing the San Juan Islands of modern-day Washington within U.S. national territory, thus ending the 12-year bloodless Pig War.

In his memoirs, Bismarck describes William as an old-fashioned, courteous, infallibly polite gentleman and a genuine Prussian officer, whose good common sense was occasionally undermined by "female influences". This was a reference to William's wife, who had been educated by, among others Johann Wolfgang von Goethe and was intellectually superior to her husband. She was also at times very outspoken in her opposition to official policies as she was a liberal. William, however, had long been strongly opposed to liberal ideas. Despite possessing considerable power as Kaiser, William left the task of governing mostly to his chancellor, limiting himself to representing the state and approving Bismarck's every policy. In private he once remarked on his relationship with Bismarck: It is difficult to be emperor under such a chancellor.

• 
  Wilhem I with his only daughter, Princess Louise, c. 1860s
• 
  Portrait of Wilhelm I, c. 1870
• 
  Wilhelm I with his nephew, Tsar Alexander II on a hunting trip together, c. 1872
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  Wilhelm I with his sister, Princess Alexandrine, c. 1882
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  Prince Wilhelm (future Wilhelm I), c. 1858

On 11 May 1878, a plumber named Emil Max Hödel failed in an assassination attempt on William in Berlin. Hödel used a revolver to shoot at the then 81-year-old Emperor, while he and his daughter, Princess Louise, paraded in their carriage on Unter den Linden. When the bullet missed, Hödel ran across the street and fired another round which also missed. In the commotion one of the individuals who tried to apprehend Hödel suffered severe internal injuries and died two days later. Hödel was seized immediately. He was tried, convicted, sentenced to death, and executed on 16 August 1878.

A second attempt to assassinate William I was made on 2 June 1878 by Karl Nobiling. As the Emperor drove past in an open carriage, the assassin fired two shots from a shotgun at him from the window of a house off the Unter den Linden. William was severely wounded and was rushed back to the palace. Nobiling shot himself in an attempt to commit suicide. While William survived this attack, the assassin died from his self-inflicted wound three months later.

Despite the fact that Hödel had been expelled from the Social Democratic Party, his actions were used as a pretext by Bismarck to ban the party. To do this, Bismarck partnered with Ludwig Bamberger, a Liberal, who had written on the subject of Socialism, "If I don't want any chickens, then I must smash the eggs." These attempts on William's life thus became the pretext for the institution of the Anti-Socialist Laws, which were introduced by Bismarck's government with the support of a majority in the Reichstag on 18 October 1878, for the purpose of fighting the socialist and working-class movement. These laws deprived the Social Democratic Party of Germany of its legal status; prohibited all organizations, workers’ mass organizations and the socialist and workers’ press; decreed confiscation of socialist literature; and subjected Social-Democrats to reprisals. The laws were extended every 2–3 years. Despite the reprisals the Social Democratic Party increased its influence among the masses. Under pressure of the mass working-class movement the laws were repealed on 1 October 1890.

In August 1878, Alexander II of Russia, William's nephew, wrote a letter (known as Ohrfeigenbrief) to him complaining about the treatment Russian interests had received at the Congress of Berlin. In response William, his wife Augusta, and his son the crown prince travelled to Russia (against the advice of Bismarck) to mend fences in face-to-face talks. However, by once again threatening to resign, Bismarck overcame the opposition of William to a closer alliance with Austria-Hungary. In October, William agreed to the Dual Alliance (Zweibund) between Germany and Austria-Hungary, which was directed against Russia.

Another assassination attempt failed on 28 September 1883 when William unveiled the Niederwalddenkmal in Rüdesheim. A group of anarchists had prepared an attack using dynamite which failed due to the wet weather.

The Berlin Conference of 1884–85 organized by Otto von Bismarck can be seen as the formalization of the Scramble for Africa. Claiming much of the left-over territories in Africa and Oceania that were yet unclaimed, Germany managed to build the large German colonial empire.

Despite the assassination attempts and William's unpopular role in the 1848 uprising, he and his wife were very popular, especially in their later years. Many people considered them the personification of "the old Prussia" and liked their austere and simple lifestyle. William died on 9 March 1888 in Berlin after a short illness, at age 90. He was buried on 16 March at the Mausoleum at Park Charlottenburg. He was succeeded by his son Frederick, who was already fatally unwell himself (suffering from throat cancer). Frederick spent the 99 days of his reign fighting his illness before dying and being succeeded by his eldest son Wilhelm on 15 June.

To honour him a large number of memorials/statues were erected all over the country over the following years. The best known among them are the Kyffhäuser monument (1890–96) in Thuringia, the monument at Porta Westfalica (1896) and the mounted statue of William at the Deutsches Eck in Koblenz (1897). The National Kaiser Wilhelm Monument in Berlin was destroyed by the government of East Berlin in 1950.

William and Augusta of Saxe-Weimar had two children:

Image	Name	Birth	Death	Notes
	Frederick III, German Emperor and King of Prussia	18 October 1831	15 June 1888(1888-06-15) (aged 56)	married (25 January 1858) Victoria, Princess Royal (1840–1901); eight children.
	Princess Louise of Prussia	3 December 1838	23 April 1923(1923-04-23) (aged 84)	married (20 September 1856) Prince Frederick of Baden (1826–1907); three children.

He had two illegitimate twin children, born from an affair with Elisa Radzwill.

Agnes Dettman (born 30 January 1824 in Posen; died 3 January 1904 in Sydney, Australia) was placed in the care of Joseph Kroll and Agnes Kroll. She later emigrated to Australia, where she started a family.

Adalbert Berengar Viktor von Hohenzollern (born 30 January 1824 in Posen; died 14 January 1882 in Marco, Ceará, Brazil) was entrusted to the care of the Ursuline convent in Posen. He became a priest and emigrated to Brazil, where he engaged in missionary work throughout the northeastern region. During this period, he fathered an illegitimate child with Maria dos Anjos Chefe da Silveira, named Manoel Chefe da Silveira.

William was a Lutheran member of the Evangelical State Church of Prussia's older Provinces. It was a United Protestant denomination, bringing together Reformed and Lutheran believers.

His full title as king of Prussia was William, by the Grace of God, King of Prussia; Margrave of Brandenburg, Burgrave of Nuremberg, Count of Hohenzollern; Sovereign and Supreme Duke of Silesia and of the County of Glatz; Grand Duke of the Lower Rhine and of Posen; Duke of Saxony, of Westphalia, of Angria, of Pomerania, Lüneburg, Holstein and Schleswig, of Magdeburg, of Bremen, of Guelders, Cleves, Jülich and Berg, Duke of the Wends and the Kassubes, of Crossen, Lauenburg and Mecklenburg; Landgrave of Hesse and Thuringia; Margrave of Upper and Lower Lusatia; Prince of Orange; Prince of Rügen, of East Friesland, of Paderborn and Pyrmont, of Halberstadt, Münster, Minden, Osnabrück, Hildesheim, of Verden, Cammin, Fulda, Nassau and Moers; Princely Count of Henneberg; Count of Mark, of Ravensberg, of Hohenstein, Tecklenburg and Lingen, of Mansfeld, Sigmaringen and Veringen; Lord of Frankfurt.

Wilhelm Island is named after him.

• List of monarchs of Prussia
• Kamerun
• Togoland
• German South West Africa
• German New Guinea
• German East Africa
• German Samoa

• De Graaf, Beatrice (2014). "Second-tier Diplomacy. Hans von Gagern and William I in their Quest for an Alternative European Order, 1813–1818". Journal of Modern European History / Zeitschrift für Moderne Europäische Geschichte / Revue d'Histoire Européenne Contemporaine. 12 (4): 546–566. JSTOR 26266157.
• Forbes, Archibald (1888). William of Germany: A Succinct Biography of William I., German Emperor and King of Prussia. Cassell.
• Hughes, Michael L. (2008). "Splendid Demonstrations: The Political Funerals of Kaiser Wilhelm I and Wilhelm Liebknecht". Central European History. 41 (2): 229–253. doi:10.1017/S0008938908000320. JSTOR 20457340. S2CID 144463141.
• Röhl, John C. G. (1998). Young Wilhelm: The Kaiser's Early Life, 1859–1888.
• Scully, Richard (2011). "The Other Kaiser: Wilhelm I and British Cartoonists, 1861-1914". Victorian Periodicals Review. 44 (1): 69–98. doi:10.1353/vpr.2011.0007. JSTOR 23079098. S2CID 153572848.
• Sterkenburgh, Frederik Frank (2017). William I and monarchical rule in Imperial Germany (Thesis). University of Warwick.
• Steinberg, Jonathan (2011). Bismarck: A Life. ISBN 978-019978252-9.
• Schwochert, Christian (2015). Kaiser Wilhelm I. Berlin: CreateSpace Independent Publishing. ISBN 978-1-5118-8283-5.

• Archontology.org – William I
• Webpage of the House of Hohenzollern (in German)
• Newspaper clippings about William I, German Emperor in the 20th Century Press Archives of the ZBW
• Texts on Wikisource:
  • Carl Schurz, Kaiser Wilhelm I, 1888

William I, German Emperor House of Hohenzollern Born: 22 March 1797 Died: 9 March 1888
Regnal titles
Preceded by Frederick William IV	King of Prussia 2 January 1861 – 9 March 1888	Succeeded by Frederick III
New creation Unification of Germany	German Emperor 18 January 1871 – 9 March 1888
Preceded by Christian IX of Denmark	Duke of Saxe-Lauenburg 1864–1876	Incorporated into the Prussian crown
Vacant Treaty of Vienna Title last held by Frederick VII of Denmark	Duke of Schleswig and Holstein 1864–1888
Preceded by Adolphe of Luxembourg as Duke of Nassau	Prince of Nassau 1866–1888
Preceded by Frederick William of Hesse as Elector of Hesse	Landgrave of Hesse Prince of Fulda 1866–1888
Preceded by Karl Fellner as Elder Mayor of Frankfurt	Lord of Frankfurt 1866–1888
Preceded by George V of Hanover as King of Hanover	Prince of East Friesland, Osnabrück, Hildesheim and Verden Count of Lingen and Tecklenburg 1866–1888
Political offices
Preceded by Francis Joseph I of Austria as Head of the Präsidialmacht of the German Confederation	Holder of the Bundespräsidium of the North German Confederation 1 July 1867 – 18 January 1871	Confederation abolished German Empire proclaimed