Alexander III with members of Romanov family
Alexander had little prospect of succeeding to the throne, as he had an elder brother, Nicholas. Even when Nicholas first displayed symptoms of poor health, the notion that he might die young was never taken seriously, and he was betrothed to Princess Dagmar of Denmark, daughter of King Christian IX of Denmark and Queen Louise of Denmark, and whose siblings included King Frederick VIII of Denmark, Alexandra, Queen of the United Kingdom and King George I of Greece. Nicholas was educated as tsesarevich, whereas Alexander received only the training of a Grand Duke. This included acquaintance with French, English and German, and military drill. On his deathbed Nicholas expressed the wish that his fiancée, Princess Dagmar of Denmark, should marry his successor. This wish was swiftly realized when on 9 November [O.S. 28 October] 1866 in the Grand Church of the Winter Palace in St. Petersburg, Alexander wed Dagmar, who converted to Orthodox Christianity and took the name Maria Feodorovna. The union proved a happy one unlike his father's.
Princess Marie Sophie Frederikke Dagmar was born at the Yellow Palace in Copenhagen. Her father was Prince Christian of Schleswig-Holstein-Sonderburg-Glücksburg, a member of a relatively impoverished princely cadet line. Her mother was Princess Louise of Hesse-Kassel. She was baptised as a Lutheran and named after her kinswoman Marie Sophie of Hesse-Kassel, Queen Dowager of Denmark as well as the medieval Danish queen, Dagmar of Bohemia. Growing up, she was known by the name Dagmar. Most of her life, she was known as Maria Feodorovna, the name which she took when she converted to Orthodoxy immediately before her 1866 marriage to the future Emperor Alexander III. She was known within her family as "Minnie". Due to the brilliant marital alliances of her father, he became known as the "Father-in-law of Europe." Her elder, and favorite, sister, Alexandra married Albert Edward, the Prince of Wales (the future King Edward VII) in March 1863. Alexandra, along with being queen consort of King Edward VII, was also mother of George V of the United Kingdom, which helps to explain the striking resemblance between their sons Nicholas II and George V. Her younger sister was Thyra, Duchess of Cumberland.
Alexander III was the second son of Alexander II and of Maria Aleksandrovna (Marie of Hesse-Darmstadt). During the first 20 years of his life, Alexander had no prospect of succeeding to the throne. His training and acquaintance was with French, English, and German, and military drill. When he became heir apparent on the death of his elder brother Nikolay in 1865, he began to study the principles of law and administration under the jurist and conservative philosopher K.P. Pobedonostsev. The tsesarevich Nikolay, on his deathbed, had expressed a wish that his fiancée, Princess Dagmar of Denmark, known as Maria Fyodorovna, should marry his successor. The marriage proved a happiest one. On March 13 (March 1, O.S.), 1881, Alexander II was assassinated, and the following day autocratic power passed to his son. Alexander III political ideal was a nation with one language, one religion, and one form of administration, he sought to strengthen and centralize the imperial administration.