the nineteenth century. Once the forces of Aleksandr Baryatinsky had captured the legendary Chechen rebel leader Shamil in 1859, the army resumed the expansion into Central Asia that had begun under Nicholas I. The capture of Tashkent was a significant victory over the Kokand Khanate, part of which was annexed in 1866. By 1867 Russian forces had captured enough territory to form the Guberniya (Governorate General) of Turkestan, the capital of which was Tashkent. The Bukhara Khanate then lost the crucial Samarkand area to Russian forces in 1868. To avoid alarming Britain, which had strong interests in protecting nearby India, Russia left the Bukhoran territories directly bordering Afghanistan and Persia nominally independent. The Central Asian khanates retained a degree of autonomy until 1917. Russia followed the United States, Britain, and France in establishing relations with Japan, and, together with Britain and France, Russia obtained concessions from China consequent to the Second Opium War (1856–1860). Under the Treaty of Aigun in 1858 and the Treaty of Beijing in 1860, China ceded to Russia extensive trading rights and regions adjacent to the Amur and Ussuri rivers and allowed Russia to begin building a port and naval base at Vladivostok. As part of the foreign policy goals in Europe, Russia initially gave guarded support to France's anti-Austrian diplomacy. A weak Franco-Russian entente soured, however, when France backed a Polish uprising against Russian rule in 1863. Russia then aligned itself more closely with Prussia by approving the unification of Germany in exchange for a revision of the Treaty of Paris and the remilitarization of the Black Sea. These diplomatic achievements came at a London conference in 1871, following France's defeat in the Franco-Prussian War. After 1871 Germany, united under Prussian leadership, was the strongest continental power in Europe. In 1873 Germany formed the loosely knit League of the Three Emperors with Russia and Austria-Hungary to prevent them from forming an alliance with France. Nevertheless, Austro-Hungarian and Russian ambitions clashed in the Balkans, where rivalries among Slavic nationalities and anti-Ottoman sentiments seethed. In the 1870s, Russian nationalist opinion became a serious domestic factor in its support for liberating Balkan Christians from Ottoman rule and making Bulgaria and Serbia quasi-protectorates of Russia. From 1875 to 1877, the Balkan crisis escalated with the rebellion in Bosnia and Herzegovina, and insurrection in Bulgaria, which the Ottoman Turks suppressed with such great cruelty that Serbia, but none of the