Russo-Turkish War (1877–1878) in the context of "United Principalities of Moldavia and Wallachia"

Constanța (UK: /kɒnˈstæntsə/, US: /kənˈstɑːn(t)sə/, Romanian: [konˈstantsa] ) is a city in the Dobruja historical region of Romania. A port city, it is the capital of Constanța County and the country's fourth largest city and principal port on the Black Sea coast. It is also the oldest continuously inhabited city in Romania, founded around 600 BC, and among the oldest in Europe.

As of the 2021 census, Constanța has a population of 263,688. The Constanța metropolitan area includes 14 localities within 30 km (19 mi) of the city. It is one of the largest metropolitan areas in Romania. Ethnic Romanians became a majority in the city in the early 20th century. The city still has small Tatar and Greek communities, which were substantial in previous centuries, as well as Turkish and Romani residents, among others. Constanța has a rich multicultural heritage, as, throughout history, it has been part of different cultures, including Roman, Byzantine, Bulgarian, and Ottoman. Following the Russo-Turkish War (1877–1878), Constanța became part of Romania, and the city, which at the time had a population of just over 5,000 inhabitants, grew significantly throughout the 20th century.

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 Kingdom of Romania (Romanian: Regatul României) was a constitutional monarchy that existed from 25 March [O.S. 13 March] 1881 with the crowning of prince Karl of Hohenzollern-Sigmaringen as King Carol I (thus beginning the Romanian royal family), until 1947 with the abdication of King Michael I and the Romanian parliament's proclamation of the Romanian People's Republic.

From 1859 to 1877, Romania evolved from a personal union of two principalities: (Moldavia and Wallachia) called the Unification of Moldavia and Wallachia also known as "The Little Union" under a single prince to an autonomous principality with a Hohenzollern monarchy. The country gained its independence from the Ottoman Empire during the 1877–1878 Russo-Turkish War (known locally as the Romanian War of Independence), after which it was forced to cede the southern part of Bessarabia in exchange for Northern Dobruja. The kingdom's territory during the reign of King Carol I, between 13 (O.S.) / 25 March 1881 and 27 September (O.S.) / 10 October 1914 is sometimes referred to as the Romanian Old Kingdom, to distinguish it from "Greater Romania", which included the provinces that became part of the state after World War I (Bessarabia, Banat, Bukovina, and Transylvania).

Carol I or Charles I of Romania (born Karl Eitel Friedrich Zephyrinus Ludwig von Hohenzollern-Sigmaringen; 20 April 1839 – 10 October [O.S. 27 September] 1914), nicknamed the King of Independence (Romanian: Regele Independenței), was the monarch of Romania from 1866 to his death in 1914, ruling as Prince (Domnitor) from 1866 to 1881, and as King from 1881 to 1914. He was elected Prince of the Romanian United Principalities on 20 April 1866 after the overthrow of Alexandru Ioan Cuza by a palace coup d'état. In May 1877, Romania was proclaimed an independent and sovereign nation. The defeat of the Ottoman Empire (1878) in the Russo-Turkish War secured Romanian independence, and he was proclaimed King on 26 March [O.S. 14 March] 1881. He was the first ruler of the Hohenzollern-Sigmaringen dynasty, which ruled the country until the proclamation of a socialist republic in 1947.

During his reign, Carol I personally led Romanian troops during the Russo-Turkish War and assumed command of the Russo-Romanian army during the siege of Plevna. The country achieved internationally recognized independence via the Treaty of Berlin, 1878 and acquired Southern Dobruja from Bulgaria in 1913. In 1883 the king entered a top-secret military alliance with the Austro-Hungarian Empire, despite popular demands against Hungary. When World War I broke out he was unable to activate the alliance. Romania remained neutral and in 1916 joined the Allies.

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.

Starting in the 19th century the Ottoman Empire's governing structure slowly transitioned and standardized itself into a Western style system of government, sometimes known as the Imperial Government. Mahmud II (r. 1808–1839) initiated this process following the disbandment and massacre of the Janissary corps, at this point a conservative bureaucratic elite, in the Auspicious Incident. A long period of reform known as the Tanzimat period started, which yielded much needed reform to the government and social contract with the multicultural citizens of the empire.

In the height of the Tanzimat period in 1876, Abdul Hamid II (r. 1876–1909) turned the Empire into a constitutional monarchy by promulgating the Empire's first Constitution, which established the short First Constitutional Era and also featured elections for a parliament. Defeat in the 1877–1878 War with Russia and dissatisfaction with Abdul Hamid lead to the "temporary" suspension of the constitution and the parliament, resulting in a modern despotism/autocracy of Abdul Hamid, during which internal reform continued. The Young Turk Revolution in 1908 started the longer lasting Second Constitutional Era and forced Abdul Hamid to reinstate the constitution, recall the parliament, and hold elections again which this time which featured political parties. However, by 1913 the Ottoman Empire was a dictatorship of the Committee of Union and Progress (CUP), led by the Three Pashas (Talat Pasha, Enver Pasha, and Cemal Pasha). This dictatorship capitalized on the developed bureaucracy created through a century of reform and centralization by undertaking genocide against Christian minorities. The CUP also undertook many reforms relating to social structure, religion, and education, which would be continued and more far reaching under Mustafa Kemal Atatürk's regime. The Union and Progress dictatorship lasted until the end of World War I, which lead to the Empire's collapse and subsequent abolition by Turkish nationalist forces led by Atatürk.

Alexandroupolis (Ἀλεξανδρούπολις, IPA: [aleks̠anˈðɾupolis̠]) or Alexandroupoli (Αλεξανδρούπολη, IPA: [aleks̠anˈðɾupoli]), also known as Alexandrople, is a port city in Greece and the capital of the Evros regional unit, in Greek Thrace. It is the largest city in Eastern Macedonia and Thrace, with a population of 71,751 and is an important port and commercial center for Northern Greece.

The city was first settled by the Ottoman Empire in the 19th century and grew into the fishing village Dedeağaç. In 1873, it became a kaza and one year later was promoted to a sanjak. The city developed into a regional trading center. Later, it became a part of Adrianople Vilayet. During the Russo-Turkish War (1877–1878), the area was briefly captured by the Russians. Ottoman rule ended with the First Balkan War, when the city was captured by Bulgaria in 1912. In the Second Balkan War, Greece took control of the city. With the Treaty of Bucharest (10 August 1913), the city returned to Bulgaria.

The Bulgarian Revival (Bulgarian: Българско възраждане, Balgarsko vazrazhdane or simply: Възраждане, Vazrazhdane, and Turkish: Bulgar ulus canlanması), sometimes called the Bulgarian National Revival, was a period of socio-economic development and national integration among Bulgarian people under Ottoman rule. It is commonly accepted to have started with the historical book, Istoriya Slavyanobolgarskaya, written in 1762 by Paisius, a Bulgarian monk of the Hilandar monastery at Mount Athos, leading to the National awakening of Bulgaria and the modern Bulgarian nationalism, and lasting until the Liberation of Bulgaria in 1878 as a result of the Russo-Turkish War of 1877–1878.