Frederick III (German: Friedrich III., Deutscher Kaiser und König von Preußen; 18 October 1831 – 15 June 1888) was German Emperor and King of Prussia for 99 days in 1888 during the Year of the Three Emperors. Frederick William Nicholas Charles (German: Friedrich Wilhelm Nikolaus Karl), known informally as Fritz, was the only son of Emperor William I, and was raised in his family's tradition of military service. Although celebrated as a young man for his leadership and successes during the Second Schleswig, Austro-Prussian and Franco-Prussian wars, he nevertheless professed a hatred of warfare, and was praised by friends and enemies alike for his humane conduct. Following the unification of Germany in 1871 his father, then King of Prussia, became the German Emperor, and on William's death at the age of 90 on 9 March 1888, the throne passed to Frederick, having by then been the Crown Prince for twenty-seven years. Frederick was suffering from cancer of the larynx and died on 15 June 1888, aged 57, following unsuccessful medical treatments for his condition.

Frederick married Princess Victoria, daughter of Queen Victoria of the United Kingdom. The couple were well matched; their shared liberal ideology led them to seek greater representation for commoners in the government. Frederick, in spite of his conservative militaristic family background, had developed liberal tendencies as a result of his ties with Britain and his studies at the University of Bonn. As the Crown Prince, he often opposed the conservative Chancellor Otto von Bismarck, particularly in speaking out against Bismarck's policy to unite Germany through force, and in urging for the power of the position of Chancellor to be curbed. Liberals in both Germany and Britain hoped that as emperor, Frederick III would move to liberalize the German Empire. Frederick and Victoria were great admirers of the Prince Consort of the United Kingdom, Victoria's father. They planned to rule as consorts, like Albert and Queen Victoria, and they planned to reform the fatal flaws in the executive branch that Bismarck had created for himself. The office of Chancellor responsible to the Emperor would be replaced with a British-style cabinet, with ministers responsible to the Reichstag. Government policy would be based on the consensus of the cabinet. Frederick "described the Imperial Constitution as ingeniously contrived chaos."

"The Crown Prince and Princess shared the outlook of the Progressive Party, and Bismarck was haunted by the fear that should the old Emperor die -- and he was now in his seventies -- they would call on one of the Progressive leaders to become Chancellor. He sought to guard against such a turn by keeping the Crown Prince from a position of any influence and by using foul means as well as fair to make him unpopular."

However, his illness prevented him from effectively establishing policies and measures to achieve this, and such moves as he was able to make were later abandoned by his son and successor, William II. The timing of Frederick's death, and the length of his reign, are important topics among historians. The reign of Frederick III is considered a potential turning point in German history; many historians believe if Frederick succeeded to the throne sooner, he would have transformed Germany into a liberal state. They argue this would have averted the events preceding World War I. Other historians contend that Frederick's influence and political leanings were greatly exaggerated, noting that he tended to defer to his father and Bismarck when confronted, and would not have dared to challenge their conservatism even as ruler. They further argue that 19th-century Germany was a deeply conservative nation, and would have opposed the implementation of liberal policies.

Frederick William was born in the New Palace at Potsdam in Prussia on 18 October 1831. He was a scion of the House of Hohenzollern, rulers of Prussia, the most powerful of the German states. Frederick's father, Prince William, was a younger brother of King Frederick William IV, and having been raised in the military traditions of the Hohenzollerns, developed into a strict disciplinarian. William fell in love with his cousin Elisa Radziwill, a Princess of the Polish nobility, but his parents felt Elisa's rank was not suitable for the bride of a Prussian Prince, and forced a more suitable match. The woman selected to be his wife, Princess Augusta of Saxe-Weimar, had been raised in the more intellectual and artistic atmosphere of Weimar, which gave its citizens greater participation in politics and limited the powers of its rulers through a constitution; Augusta was well known across Europe for her liberal views. The pair did not have a happy marriage because of their differences, so Frederick grew up in a troubled household, leaving him with memories of a lonely childhood. He had one sister, Louise (later Grand Duchess of Baden) who was eight years his junior and very close to him.

Frederick grew up during a tumultuous political period as the concept of liberalism in Germany, which evolved during the 1840s, was gaining widespread and enthusiastic support. The liberals sought a unified Germany, and were constitutional monarchists who desired a constitution to ensure equal protection under the law, the protection of property, and the safeguarding of basic civil rights. Overall, the liberals desired a government ruled by popular representation. When Frederick was 17, these emergent nationalistic and liberal sentiments sparked a series of political uprisings across the German states and elsewhere in Europe. In Germany, their goal was to protect freedoms such as the freedom of assembly and freedom of the press, and to create a German parliament and constitution. Although the uprisings ultimately brought about no lasting changes, liberal sentiments remained an influential force in German politics throughout Frederick's life.

Despite the value placed by the Hohenzollern family on a traditional military education, Augusta insisted that her son receive a classical education as well. Accordingly, Frederick was thoroughly tutored in both military traditions and the liberal arts. He was a talented student, particularly good at foreign languages, becoming fluent in English and French, and studying Latin. He also studied history, geography, physics, music and religion, and excelled at gymnastics; as required of a Prussian Prince, he became a very good rider. Hohenzollern princes were made familiar with the military traditions of their dynasty at an early age; Frederick was ten when he was commissioned as a second lieutenant into the First Infantry Regiment of Guards, and invested with the Order of the Black Eagle. As he grew older he was expected to maintain an active involvement in military affairs, but at the age of 18 he broke with family tradition and entered the University of Bonn. His time spent at the university, coupled with the influence of his less conservative family members, were instrumental in his embrace of liberal beliefs.

Royal marriages of the 19th century were arranged to secure alliances and to maintain blood ties among the European nations. As early as 1851, Queen Victoria of Great Britain and her consort Prince Albert were making plans to marry their eldest daughter Victoria, Princess Royal of Great Britain and Ireland, to Frederick. The royal dynasty in Britain was predominantly German; there was little British blood in Queen Victoria, and none in her husband. The monarchs desired to maintain their family's blood ties to Germany, and Prince Albert further hoped that the marriage would lead to the liberalization and modernization of Prussia. King Leopold I of Belgium, uncle of the British monarchs, also favoured this pairing; he had long treasured Baron Stockmar's idea of a marriage alliance between Britain and Prussia. Frederick's father, Prince William, had no interest in the arrangement, hoping instead for a Russian Grand Duchess as his daughter-in-law. However, Princess Augusta was greatly in favour of a match for her son that would bring closer connections with Britain. The betrothal of the young couple was announced in April 1856, and their marriage took place on 25 January 1858, in the Chapel of St. James's Palace, London. To mark the occasion, Frederick was promoted to Major-General in the Prussian army. The newlyweds were compatible from the start, and their marriage was a loving one; Victoria too had received a liberal education, and shared her husband's views. The couple had eight children: Wilhelm in 1859, Charlotte in 1860, Henry in 1862, Sigismund in 1864, Victoria in 1866, Waldemar in 1868, Sophie in 1870 and Margaret in 1872. Sigismund died at the age of 2 and Waldemar at age 11, and their eldest son, William, suffered from a withered arm — probably due to his difficult and dangerous breech birth, although it could have also resulted from a mild case of cerebral palsy. William, who became emperor after Frederick's death, shared none of his parent's liberal ideas; his mother viewed him as a "complete Prussian". This difference in ideology created a rift between William and his parents, and relations between them were strained throughout their lives.

When his father succeeded to the Prussian throne as King William I on 2 January 1861, Frederick became the Crown Prince. Already twenty-nine years old, he would be Crown Prince for a further twenty-seven years. The new king was initially considered politically neutral; Frederick and Prussia's liberal elements hoped that he would usher in a new era of liberal policies. The liberals managed to greatly increase their majority in the Prussian Diet, but William soon showed that he preferred the conservative ways. On the other hand, Frederick declared himself in complete agreement with the "essential liberal policy for internal and foreign affairs". Because William was a dogmatic soldier and unlikely to change his ideas at the age of sixty-four, he regularly clashed with the Diet over policies. In September 1862, one such disagreement almost led to Frederick being crowned and replacing his father as king; William threatened to abdicate when the Diet refused to fund his plans for the army's reorganization. Frederick was appalled by this action, and said that an abdication would "constitute a threat to the dynasty, country and Crown". William reconsidered, and instead appointed Otto von Bismarck as Minister-President. The appointment of Bismarck, an authoritarian who often ignored or overruled the Diet, set Frederick on a collision course with his father and led to his exclusion from affairs of state for the rest of William's reign. Frederick insisted on bloodless "moral conquests", unifying Germany by liberal and peaceful means, but it was Bismarck's policy of blood and iron that prevailed. Frederick was severely reproached by his father for his liberal ideas, so he spent a large portion of time in England where Queen Victoria frequently allowed him to represent her at ceremonies and social functions.

Frederick experienced his first combat in the Second Schleswig War. Appointed to supervise the supreme German Confederation commander Field Marshal Wrangel and his staff, the Crown Prince tactfully managed disputes between Wrangel and the other officers. The Prussians and their Austrian allies defeated the Danes and conquered the southern part of Jutland, but after the war they spent two years politicking to assume leadership of the German states. This culminated in the Austro-Prussian War, and although Frederick had opposed a war against Austria, he accepted command of one of Prussia's three armies, with General Leonhard Graf von Blumenthal as his chief of staff. The timely arrival of his II Army was crucial to the Prussian victory in 1866 at the decisive Battle of Königgrätz, which won the war for Prussia. After the battle, William presented Frederick with the Order Pour le Mérite for his personal gallantry on the field and leadership of the II Army. A few days before Königgrätz, Frederick had written to his wife, expressing his hope that this would be the last war he would have to fight. On the third day of the battle he wrote to her again: "Who knows whether we may not have to wage a third war in order to keep what we have now won?"

Four years later Frederick was in action again, this time during the Franco-Prussian War of 1870, in which he commanded the III Army, consisting of troops from the southern German states. He was praised for his leadership after defeating the French at the battles of Wörth and Wissembourg, and met with further successes at the Battle of Sedan and during the Siege of Paris. Frederick's humane treatment of his country's foes earned him their respect and the plaudits of neutral observers. After the Battle of Wörth, a London journalist witnessed the Crown Prince's many visits to wounded Prussian soldiers and lauded his deeds, extolling the love and respect the soldiers held for Frederick. Following his victory, Frederick had remarked to two Paris journalists, "I do not like war gentlemen. If I should reign I would never make it." One French journalist remarked that "the Crown Prince has left countless traits of kindness and humanity in the land that he fought against." For his behaviour and accomplishments, the London Times wrote a tribute to Frederick in July 1871, stating that "the Prince has won as much honour for his gentleness as for his prowess in the war".

In 1871, following Prussia's victories, the German states were united into the German Empire, with William as the Emperor and Frederick as heir to the new German monarchy. Bismarck, now Chancellor, disliked Frederick and distrusted the liberal attitudes of the Crown Prince and Princess. Often at odds with his father's and Bismarck's policies and actions, Frederick sided with the country's liberals in their opposition to the expansion of the empire's army. His protests against William's rule peaked at Danzig, where at an official reception in the city he loudly denounced Bismarck's restrictions on freedom of the press. Consequently, Frederick was excluded from positions of political power throughout his father's reign. Retaining his military portfolio, he continued to represent Germany and its Emperor at ceremonies, weddings, and celebrations, such as Queen Victoria's Golden Jubilee in 1887. The Crown Prince also became involved in many public works projects, such as the establishment of schools and churches in the area of Bornstädt near Potsdam. To assist his father's effort to turn Berlin, the capital city, into a great cultural centre, he was appointed Protector of Public Museums; it was largely due to Frederick that considerable artistic collections were acquired, housed in Berlin's new Kaiser Friedrich Museum (later known as the Bode Museum) after his death.

Germany's progressive elements hoped that William's death, and thus Frederick's succession, would usher the country into a new era governed along liberal lines. The conservative William, however, lived a long life, dying at the age of 90 on 9 March 1888. By that time Frederick was 57 years old and suffering from a debilitating cancer of the larynx. He viewed his illness with dismay, crying "To think I should have such a horrid disgusting illness ... I had so hoped to have been of use to my country." He received conflicting medical advice regarding treatment. In Germany, Doctor Ernst von Bergmann proposed to remove the larynx completely, but his colleague, Doctor Rudolf Virchow, disagreed; such an operation had never been performed without the death of the patient. The British doctor Sir Morell Mackenzie, who had diagnosed the cancer, advised a tracheotomy, to which Frederick and his wife agreed. On 8 February, a month before his father died, a cannula was fitted to allow Frederick to breathe; for the remainder of his life he was unable to speak and often communicated through writing. During the operation, Dr. Bergmann almost killed him by missing the incision in the windpipe and forcing the cannula into the wrong place. Frederick started to cough and bleed, and Bergmann placed his forefinger into the wound to enlarge it. The bleeding subsided after two hours, but Bergmann's actions resulted in an abscess in Frederick's neck, producing pus which gave the new Emperor discomfort for the remaining months of his life. Later, Frederick would ask "Why did Bergmann put his finger in my throat?" and complain that "Bergmann ill-treated [me]".

In spite of his illness, Frederick did his best to fulfil his obligations as Emperor. Immediately after the announcement of his accession, he took the ribbon and star of his Order of the Black Eagle from his jacket and pinned it on the dress of his wife; he was determined to honor her position as Empress. As the German Emperor, he officially received Queen Victoria of the United Kingdom and King Oscar II of Sweden and Norway, and attended the wedding of his son Prince Henry to his niece Princess Irene. However, Frederick reigned for only 99 days, and was unable to bring about much lasting change. An edict he penned before he ascended to the throne that would limit the powers of the chancellor and monarch under the constitution was never put into effect, although he did force Robert von Puttkammer to resign as Prussian Minister of the Interior on 8 June, when evidence indicated that Puttkammer had interfered in the Reichstag elections. Dr. Mackenzie wrote that the Emperor had "an almost overwhelming sense of the duties of his position". In a letter to Lord Napier, Empress Victoria wrote "The Emperor is able to attend to his business, and do a great deal, but not being able to speak is, of course, most trying." Frederick had the fervour but not the time to accomplish his desires, lamenting in May 1888, "I cannot die ... What would happen to Germany?" Frederick III died on 15 June 1888, and was succeeded by his 29-year-old son William II. Frederick is buried in a mausoleum attached to the Friedenskirche in Potsdam. After his death, he was referred to by the British Prime Minister William Ewart Gladstone as the "Barbarossa of German liberalism". Empress Victoria went on to continue spreading Frederick's thoughts and ideals throughout Germany, but no longer had power within the government.