A Balkan coalition pushed Ottomans back to Constantinople's gates
The Russo-Turkish War of 1877–1878 matched the Ottoman Empire against a Russian-led coalition with Romania, Serbia, and Montenegro. Russian aims of recovering losses and aiding Balkan Christians met Ottoman weakness after decades of contested reform.
Russia wanted to undo what it had lost in the Crimean War of 1853–1856, regain its footing on the Black Sea and back the movements trying to prise Balkan peoples away from Ottoman rule. The coalition won decisively, driving Turkish forces right back to Constantinople before the Western European powers stepped in. Russia took Kars and Batum in the Caucasus and annexed the Budjak. Romania, Serbia and Montenegro, already independent in practice, formally declared it, and Bulgaria became autonomous with Russian help after nearly five centuries under the sultans, from 1396 to 1878. Greece picked up parts of Thessaly and Arta.
The treatment of Christians was a live grievance. The 1856 Paris treaty required equal rights for Christians and Muslims, and the Ottoman Reform Edict issued just before it scrapped the jizya poll tax and opened the army to non-Muslims. Yet in 1858 Maronite peasants in northern Lebanon rose against Druze overlords, the conflict spread into civil war, and some 10,000 Maronites were killed. Foreign Minister Mehmed Fuad Pasha restored order by executing agitators, including the governor, but France still landed a fleet in September 1860, Britain joined to keep French influence in check, and the sultan accepted a Christian governor for Lebanon approved by the European powers.
The empire itself was weakening despite having been on the winning side in Crimea. Loans taken at punishing interest left unpayable debts, and more than 600,000 Circassian Muslims expelled by Russia from the Caucasus had to be resettled at Black Sea and Balkan ports at great cost.
Europe's balance was also shifting. Prussia under Bismarck beat Austria in 1866 and France in 1870, ending the Concert of Europe, while Britain, absorbed by Ireland, stayed aloof. Bismarck formed the Three Emperors' League with Russia and Austria-Hungary to isolate France, which responded by encouraging national revolts; Russia, for its part, courted Balkan Slavs with Pan-Slavism, an idea that implied dismantling both the Habsburg and Ottoman empires.
Source: Russo-Turkish War (1877–1878)