The last and most tenacious of the Polish uprisings of the mid- nineteenth century erupted in the Russian-occupied sector in January 1863. Following Russia's disastrous defeat in the Crimean War, the government of Tsar Alexander II enacted a series of liberal reforms, including liberation of the serfs throughout the empire. High-handed imposition of land reforms in Poland aroused hostility among the landed nobles and a group of young radical intellectuals influenced by Karl Marx and the Russian liberal Alexander Herzen. Repeating the pattern of 1830-31, the open revolt of the January Insurrection by Congress Poland failed to win foreign backing. Although its socially progressive program could not mobilize the peasants, the rebellion persisted stubbornly for fifteen months. After finally crushing the insurgency in August 1864, Russia abolished the Congress Kingdom of Poland altogether and revoked the separate status of the Polish lands, incorporating them directly as the Western Region of the Russian Empire. The region was placed under the dictatorial rule of Mikhail Muravev, who became known as the Hangman of Wilno. All Polish citizens were assimilated into the empire. When Russia officially emancipated the Polish serfs in early 1864, it removed a major rallying point from the agenda of potential Polish revolutionaries.