Following Alexander II's assassination, Alexander III's reign tightened autocratic control, with the Okhrana policing revolutionaries and anti-Semitic pogroms occurring. Economic modernization under Sergei Witte included the Trans-Siberian railway. Nicholas II's rule saw defeat in the Russo-Japanese War, leading to the 1905 Revolution, which forced concessions and a constitution. Prime Minister Stolypin's land reforms aimed to aid peasants but he was assassinated in 1911. Russia's involvement in WWI led to massive losses and domestic unrest, culminating in the 1917 February Revolution, where Nicholas II abdicated, setting the stage for the Bolshevik takeover amid ongoing chaos.