Alexander pivoted towards foreign policy and sold Alaska to the United States in 1867, fearing the remote colony would fall into British hands if there were another war. He sought peace, moved away from bellicose France when Napoleon III fell in 1871, and in 1872 joined with Germany and Austria in the League of the Three Emperors that stabilized the European situation. Despite his otherwise pacifist foreign policy, he fought a brief war with the Ottoman Empire in 1877–78, leading to the independence of the Bulgarian, Montenegrin, Romanian and Serbian states, pursued further expansion into Siberia and the Caucasus, and conquered Turkestan, also approving plans leading to the Circassian genocide. Although disappointed by the results of the Congress of Berlin in 1878, Alexander abided by that agreement. Among his greatest domestic challenges was an uprising in Poland in 1863, to which he responded by stripping that land of its separate constitution and incorporating it directly into Russia. Alexander was proposing additional parliamentary reforms to counter the rise of nascent revolutionary and anarchistic movements when he was assassinated in 1881.