Early life and education
Frederick William, ca. 1841
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, then 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. Because of their differences, the couple did not have a happy marriage and, as a result, Frederick grew up in a troubled household, which left 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 also had a very good relationship with his uncle, King Frederick William IV, who has been called "the romantic on the throne". 
Crown Prince Frederick William of Prussia, 1867, by Oskar Begas
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 also receive a classical education. Accordingly, Frederick was thoroughly tutored in both military traditions and the liberal arts. His private tutor was Ernst Curtius, a famous archaeologist. Frederick 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 where he studied history, law and governance and public policy. During his time at Bonn (1850-1852), his teachers included Ernst Moritz Arndt and Friedrich Christoph Dahlmann. His time spent at the university, coupled with the influence of less conservative family members, were instrumental in his embrace of liberal beliefs.
In 1853, Frederick was initiated into Freemasonry by his father, then Prince William of Prussia, and would later become Master of the Order of the Grand Landlodge of the Freemasons of Germany. During his brief reign, he would serve as the patron of the German Freemasons.
Marriage and family
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 the United Kingdom and her German-born husband, Prince Albert, were making plans to marry their eldest daughter, Victoria, Princess Royal, 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 monarch and consort, 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. In 1851, his mother sent Frederick to England, ostensibly to visit the Great Exhibition but in truth she hoped that the cradle of liberalism and home of the industrial revolution would have a positive influence on her son. Prince Albert took Frederick under his wing during his stay but it was Albert's daughter, only eleven at the time, who guided the German prince around the Exhibition. Frederick only knew a few words of English, while Victoria could converse fluently in German. He was impressed by her mix of innocence, intellectual curiosity and simplicity, and their meeting proved to be a success. A regular exchange of letters between Victoria and Frederick followed.
Frederick proposed to Victoria in 1855, when she was 14 years old. The betrothal of the young couple was announced on May 19, 1857 at Buckingham Palace and the Prussian Court, and their marriage took place on 25 January 1858 in the Chapel Royal of St. James's Palace, London. To mark the occasion, Frederick was promoted to Major-General in the Prussian army. Although it was an arranged marriage, 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. Of the two, Victoria was the dominant one in the relationship. The couple often resided at the Crown Prince's Palace and had eight children: Wilhelm in 1859, Charlotte in 1860, Henry in 1862, Sigismund in 1864, Victoria in 1866, Waldemar in 1868, Sophia in 1870 and Margaret in 1872. Sigismund died at the age of 2 and Waldemar at age 11, and their eldest son, Wilhelm, 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. Wilhelm, 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 Wilhelm and his parents, and relations between them were strained throughout their lives.
Emperor Frederick III 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.