In 1868, a treaty turned Kokand into a Russian vassal state. The now powerless Khudayar Khan spent his energies improving his lavish palace. Western visitors were impressed by the city of 80,000 people, which contained some 600 mosques and 15 madrasahs. Insurrections against Russian rule and Khudayar’s oppressive taxes forced him into exile in 1875. He was succeeded by his son, Nasruddin Khan, whose anti-Russian stance provoked the annexation of Kokand (after six months of fierce fighting) by Generals Konstantin von Kaufman and Mikhail Skobelev. In January 1876, Tsar Alexander II stated that he had been forced to "... yield to the wishes of the Kokandi people to become Russian subjects." The Khanate of Kokand was declared abolished, and incorporated into the Fergana Oblast of Russian Turkestan.