Treaty of Berlin (1878) in the context of "League of Prizren"

The Kingdom of Serbia was a country located in the Balkans which was created when the ruler of the Principality of Serbia, Milan I, was proclaimed king in 1882. Since 1817, the Principality was ruled by the Obrenović dynasty (replaced by the Karađorđević dynasty for a short time). The Principality of Serbia, under the suzerainty of the Turkish Empire, de facto achieved full independence when the very last Ottoman troops left Belgrade in 1867. The Congress of Berlin in 1878 recognized the formal independence of the Principality of Serbia, and in its composition Nišava, Pirot, Toplica and Vranje districts entered the South part of Serbia.

In 1882, Serbia was elevated to the status of a kingdom, initially maintaining a foreign policy friendly to Austria-Hungary before turning to the Russian Empire and France following a coup d'état in 1903. Between 1912 and 1913, Serbia greatly enlarged its territory through engagement in the First and Second Balkan Wars – Sandžak-Raška, Kosovo Vilayet and Vardar Macedonia were annexed. At the end of World War I in 1918 it united with Vojvodina and the Kingdom of Montenegro, and in December 1918 it merged with the newly created State of Slovenes, Croats and Serbs to form the Kingdom of Serbs, Croats and Slovenes (later known as Kingdom of Yugoslavia) under the continued rule of the Karađorđević dynasty.

Romania is a country located at the crossroads of Central, Eastern and Southeast Europe. It borders Ukraine to the north and east, Hungary to the west, Serbia to the southwest, Bulgaria to the south, Moldova to the east, and the Black Sea to the southeast. It has a mainly continental climate, and an area of 238,397 km (92,046 sq mi) with a population of 19 million people. Romania is the twelfth-largest country in Europe and the sixth-most populous member state of the European Union. Europe's second-longest river, the Danube, empties into the Danube Delta in the southeast of the country. The Carpathian Mountains cross Romania from the north to the southwest and include Moldoveanu Peak, at an altitude of 2,544 m (8,346 ft). Bucharest is the country's capital, largest urban area, and financial centre. Other major urban areas include Cluj-Napoca, Timișoara, Iași, Constanța and Brașov.

Settlement in the territory of modern Romania began in the Lower Paleolithic, later becoming the Dacian Kingdom before Roman conquest and Romanisation. The modern Romanian state was formed in 1859 with the unification of Moldavia and Wallachia under Alexandru Ioan Cuza, becoming the Kingdom of Romania in 1881 under Carol I of Romania. Romania gained independence from the Ottoman Empire in 1877, formalised by the Treaty of Berlin. After World War I, Transylvania, Banat, Bukovina, and Bessarabia joined the Old Kingdom, forming Greater Romania, which reached its largest territorial extent. In 1940, under Axis pressure, Romania lost territories to Hungary, Bulgaria, and the Soviet Union. Following the 1944 Romanian coup d'état, Romania switched sides to join the Allies. After World War II, it regained Northern Transylvania through the Paris Peace Treaties. Under Soviet occupation, King Michael I was forced to abdicate, and Romania became a socialist republic and Warsaw Pact member. After the uniquely violent Romanian revolution in December 1989, Romania began a transition to liberal democracy and a market economy.

At the Congress of Berlin (13 June – 13 July 1878), the major European powers revised the territorial and political terms imposed by the Russian Empire on the Ottoman Empire by the Treaty of San Stefano (March 1878), which had ended the Russo-Turkish War of 1877–1878. The Congress was the result of escalating tensions; particularly British opposition to Russian hegemony over the Ottoman Empire in the Balkans, through the creation of a Russian-aligned 'Greater Bulgaria'. To secure the European balance of power in favour of its splendid isolation achieved after the Crimean War, Britain stationed the Mediterranean Fleet near Constantinople to enforce British demands. To avoid war, Otto von Bismarck, Chancellor of the newly formed German Empire, was asked to mediate a solution that would restore the Ottoman Empire's position as a counterbalance to Russian influence in the Mediterranean and the Balkans, in line with the principles of the 1856 Treaty of Paris.

Attended by delegates from Europe's then six great powers: Russia, Great Britain, France, Austria-Hungary, Italy, and Germany; the Ottomans as well as representatives of four Balkan states (Greece, Serbia, Romania and Montenegro), the Congress culminated in the Treaty of Berlin (13 July 1878). This agreement essentially dismantled the autonomous Greater Bulgarian State envisaged at San Stefano, and reorganised the borders of south-eastern Europe. The main results were the Austro-Hungarian forcible occupation of Bosnia and Herzegovina, the British de facto annexation of Cyprus under false pretenses, and the formal recognition of the self-declared independence of Romania, Serbia and Montenegro; allies of Russia in the previous war. While the settlement averted war, it exacerbated nationalist grievances in the Balkans and deepened the rivalry between Britain and Russia (The Great Game), contributing to long-term regional instability that foreshadowed the Balkan Wars and World War I.

The Great Eastern Crisis of 1875–1878 began in the Ottoman Empire's administrative territories in the Balkan Peninsula in 1875, with the outbreak of several uprisings and wars that resulted in the intervention of international powers, and was ended with the Treaty of Berlin in July 1878.

The war is referred to differently in various languages of the peoples involved in it due to differing sociocultural backgrounds. In Serbo-Croatian and Turkish, the war is likewise referred to as Velika istočna kriza ("Great Eastern Crisis") and Şark Buhranı ("Eastern Crisis") respectively. However, the occasionally used Turkish name Ramazan Kararnamesi ("Decree of Ramadan") refers specifically to the sovereign default declared on 30 October 1875 in historiography while 93 Harbi ("War of 93") refers to the Russo-Turkish War (the year 1293 of the Islamic Rumi calendar corresponding to the year 1877 on the Gregorian calendar).

The Principality of Serbia (Serbian: Књажество Србија, romanized: Knjažestvo Srbija) was an autonomous, later sovereign state in the Balkans that came into existence as a result of the Serbian Revolution, which lasted between 1804 and 1817. Its creation was negotiated first through an unwritten agreement between Miloš Obrenović, leader of the Second Serbian Uprising, and Ottoman official Marashli Pasha. It was followed by the series of legal documents published by the Sublime Porte in 1828, 1829 and finally, 1830—the Hatt-i Sharif. Its de facto independence ensued in 1867, following the evacuation of the remaining Ottoman troops from the Belgrade Fortress and the country; its independence was recognized internationally in 1878 by the Treaty of Berlin. In 1882 the country was elevated to the status of kingdom.

The Tsardom of Bulgaria (Bulgarian: Царство България, romanized: Tsarstvo Bŭlgariya), also known as the Third Bulgarian Tsardom (Bulgarian: Трето Българско Царство, romanized: Treto Bŭlgarsko Tsarstvo), usually known in English as the Kingdom of Bulgaria, or simply Bulgaria, was a constitutional monarchy in Southeastern Europe, which was established on 5 October [O.S. 22 September] 1908, when the Bulgarian state was raised from a principality to a tsardom.

Prince Ferdinand, founder of the royal family, was crowned as tsar at the Declaration of Independence, mainly because of his military plans and for seeking options for unification of all lands in the Balkans region with an ethnic Bulgarian majority (lands that had been seized from Bulgaria and given to the Ottoman Empire in the Treaty of Berlin). He and his successors were reckoned as kings internationally.

The Vilayet of Kosovo (Ottoman Turkish: ولايت قوصوه, Vilâyet-i Kosova; Turkish: Kosova Vilayeti; Albanian: Vilajeti i Kosovës; Serbian: Косовски вилајет, Kosovski vilajet) was a first-level administrative division (vilayet) of the Ottoman Empire in the Balkan Peninsula which included the modern-day territory of Kosovo and the north-western part of the Republic of North Macedonia. The areas today comprising Sandžak (Raška) region of Serbia and Montenegro, although de jure under Ottoman control, were de facto under Austro-Hungarian occupation from 1878 until 1909, as provided under Article 25 of the Treaty of Berlin. Üsküb (Skopje) functioned as the capital of the province. Its population of 32,000 made it the largest city in the province, followed by Prizren at 30,000.

The vilayet stood as a microcosm of Ottoman society; incorporated within its boundaries were diverse groups of peoples and religions: Albanians, Serbs, Bosniaks; Muslims and Christians, both Eastern Orthodox and Catholic. The province was renowned for its craftsmen and important cities such as İpek, where distinct Ottoman architecture and public baths were erected, some of which can still be seen today. The birthplace of the Albanian national identity was first articulated in Prizren, by the League of Prizren members in 1878.

The Principality of Bulgaria (Bulgarian: Княжество България, romanized: Knyazhestvo Balgariya) was a vassal state under the suzerainty of the Ottoman Empire. It was established by the Treaty of Berlin in 1878.

After the Russo-Turkish War ended with a Russian victory, the Treaty of San Stefano was signed by Russia and the Ottoman Empire on 3 March 1878. Under this, a large Bulgarian vassal state was agreed to, which was significantly larger: its lands encompassed nearly all ethnic Bulgarians in the Balkans, and included most of Moesia, Thrace and Macedonia, stretching from the Black Sea to the Aegean. However, the United Kingdom and Austria-Hungary were against the establishment of such a large Russian client state in the Balkans, fearing it would shift the balance of power in the Mediterranean. Due to this, the great powers convened and signed the Treaty of Berlin, superseding the Treaty of San Stefano, which never went into effect. This created a much smaller principality, alongside an autonomous Eastern Rumelia within the Ottoman Empire.