The Ottoman Empire is losing power in Europe. The Congress of Berlin takes steps to fill this void. After skillful negotiations, Austria-Hungary occupies and administers Bosnia, Herzegovina, and the Sanjak (Sandzak) of Novi Pazar in perpetuity, although formal sovereignty remains with the Ottoman Empire. But it will take Habsburg troops a full five years to complete the occupation, and even then, after 5,000 casualties, vast swathes of countryside remain in the hands of guerrilla fighters. Bosnia-Herzegovina will undergo a vast and effective modernization program.
