Nicholas II or Nikolai II was the last reigning Emperor of Russia, King of Congress Poland, and Grand Duke of Finland from 1 November 1894 until his abdication on 15 March 1917. During his reign, Nicholas gave support to the economic and political reforms promoted by his prime ministers, Sergei Witte and Pyotr Stolypin. He advocated modernisation based on foreign loans and close ties with France, but resisted giving the new parliament major roles. Ultimately, progress was undermined by Nicholas's commitment to autocratic rule, strong aristocratic opposition and defeats sustained by the Russian military in the Russo-Japanese War and World War I. By March 1917, public support for Nicholas had collapsed and he was forced to abdicate, thereby ending the Romanov dynasty's 304-year rule of Russia (1613–1917).

The emperor and autocrat of all Russia, also translated as emperor and autocrat of all the Russias, was the official title of the Russian monarch from 1721 to 1917.