Principality of Serbia (early medieval) in the context of "Republic of Serbia"

Montenegro is a country in Southeast Europe, on the Balkan Peninsula. Its 25 municipalities have a total population of 633,158 people in an area of 13,883 km (5,360 sq mi). It is bordered by Serbia to the northeast, Bosnia and Herzegovina to the northwest, Kosovo to the east, Albania to the southeast, and Croatia to the west, and has a coastline along the Adriatic Sea to the southwest. The capital and largest city is Podgorica, while Cetinje is the Old Royal Capital and cultural centre.

Before the arrival of the Slav peoples in the Balkans in the 6th and 7th centuries CE, the area now known as Montenegro was inhabited principally by people known as Illyrians.During the Early Medieval period, three principalities were located on the territory of modern-day Montenegro: Duklja, roughly corresponding to the southern half; Travunia, the west; and Rascia proper, the north. The Principality of Zeta emerged in the 14th and 15th centuries. From the late 14th century to the late 18th century, large parts of southern Montenegro were ruled by the Venetian Republic and incorporated into Venetian Albania. The name Montenegro was first used to refer to the country in the late 15th century. After falling under Ottoman Empire rule, Montenegro gained semi-autonomy in 1696 under the rule of the House of Petrović-Njegoš, first as a theocracy and later as a secular principality. Montenegro's independence was recognised by the Great Powers at the Congress of Berlin in 1878. In 1910, the country became a kingdom. After World War I, the kingdom became part of Yugoslavia. Following the breakup of Yugoslavia, the republics of Serbia and Montenegro together proclaimed a federation. In June 2006 Montenegro declared its independence following a referendum.

Serbia, officially the Republic of Serbia, is a landlocked country in Southeast and Central Europe. Located in the Balkans, it borders Hungary to the north, Romania to the northeast, Bulgaria to the southeast, North Macedonia to the south, Croatia to the northwest, Bosnia and Herzegovina to the west, and Montenegro to the southwest. Serbia also claims to share a border with Albania through the disputed territory of Kosovo. Serbia has about 6.6 million inhabitants, excluding Kosovo. Serbia's capital, Belgrade, is also the largest city in the country.

Continuously inhabited since the Paleolithic age, the territory of modern-day Serbia faced Slavic migrations in the 6th century. Several regional states were founded in the Early Middle Ages and were at times recognised as tributaries to the Byzantine, Frankish and Hungarian kingdoms. The Serbian Kingdom obtained recognition by the Holy See and Constantinople in 1217, reaching its territorial apex in 1346 as the Serbian Empire. By the mid-16th century, the Ottoman Empire annexed the entirety of modern-day Serbia; their rule was at times interrupted by the Habsburg Empire, which began expanding towards Central Serbia from the end of the 17th century while maintaining a foothold in Vojvodina. In the early 19th century, the Serbian Revolution established the nation-state as the region's first constitutional monarchy, which subsequently expanded its territory.

The Slavs or Slavic people are a major ethnic group in Europe. They speak Slavic languages and preserve Slavic culture. There are 13 Slavic countries in Europe, which include: Poland, the Czech Republic, Slovakia, Russia, Belarus, Ukraine, Slovenia, Croatia, Bosnia and Herzegovina, Serbia, Montenegro, North Macedonia, and Bulgaria; the Slavs comprise a population of around 300 million people. There are three different Slavic ethnic groups: the West Slavs, the East Slavs, and the South Slavs; the Poles, Silesians, Kashubians, Sorbs, Czechs, and Slovaks are West Slavs; Russians, Belarusians, Ukrainians, and Rusyns are East Slavs; while Slovenes, Resians, Croats, Bosniaks, Serbs, Montenegrins, Torlakians, the Gorani, the Torbeši, Macedonians, and Bulgarians are South Slavs. Slavs are geographically distributed throughout the northern parts of Eurasia; they predominantly inhabit Central Europe, Eastern Europe, Southeastern Europe, and Northern Asia, though there is a large Slavic minority scattered across the Baltic states and Central Asia, and a substantial Slavic diaspora in the Americas, Western Europe, and Northern Europe.

Early Slavs lived during the Migration Period and the Early Middle Ages (approximately from the 5th to the 10th century AD), and came to control large parts of Central, Eastern, and Southeast Europe between the sixth and seventh centuries. Beginning in the 7th century, they were gradually Christianized. By the 12th century, they formed the core population of a number of medieval Christian states: East Slavs in the Kievan Rus', South Slavs in the Bulgarian Empire, the Principality of Serbia, the Duchy of Croatia and the Banate of Bosnia, and West Slavs in the Principality of Nitra, Great Moravia, the Duchy of Bohemia, and the Kingdom of Poland.

Duklja (Serbian Cyrillic: Дукља; Greek: Διόκλεια, romanized: Diokleia; Latin: Dioclea) was a medieval South Slavic state which roughly encompassed the territories of modern-day southeastern Montenegro, from the Bay of Kotor in the west to the Bojana river in the east, and to the sources of the Zeta and Morača rivers in the north. First mentioned in 10th– and 11th-century Byzantine chronicles, it was a vassal of the Bulgarian Empire between 997 and 1018, and then of the Byzantine Empire until it became independent in 1040 under Stefan Vojislav (fl. 1034–43) who rose up and managed to take over territories of the earlier Serbian Principality, founding the Vojislavljević dynasty. Between 1043 and 1080, under Mihailo Vojislavljević (r.  1050–81), and his son, Constantine Bodin (r.  1081–1101), Duklja saw its apogee. Mihailo was given the nominal title King of Slavs by the Pope after having left the Byzantine camp and supported an uprising in the Balkans, in which his son Bodin played a central part. Having incorporated the Serbian hinterland (known as Grand Principality of Serbia, and anachronistically as Raška) and installed vassal rulers there, this maritime principality emerged as the most powerful Serb polity, seen in the titles used by its rulers ("Prince of Serbia", "of Serbs"). However, its rise was short-lived, as Bodin was defeated by the Byzantines and imprisoned; pushed to the background, his relative and vassal Vukan became independent in Raška, which continued the fight against the Byzantines while Duklja was struck with civil wars. Between 1113 and 1149 Duklja was the centre of Serbian–Byzantine conflict, with members of the Vojislavljević as protégés of either fighting each other for power. Duklja was then incorporated as a crown land of the Grand Principality of Serbia ruled by the Vukanović dynasty, subsequently known as Zeta, remaining so until the fall of the Serbian Empire in the 14th century.

Travunia (Serbo-Croatian: Travunija / Травунија; Greek: Τερβουνία, romanized: Tervounía; Ancient Greek: Τερβουνία, romanized: Terbounía; Latin: Tribunia) was a South Slavic medieval principality that was part of Medieval Serbia (850–1371), and later the Medieval Bosnia (1373–1482). The principality became hereditary in a number of noble houses, often kin to the ruling dynasty. The region came under Ottoman rule in 1482. Its seat was in the city of Trebinje.

In the 9th and 10th centuries, the Župa of Travunia was held by the Belojević noble family, who were entitled the rule during the reign of Prince Vlastimir (r. 830–850), of the Vlastimirović dynasty. After the death of Časlav, the last dynastic member, the principality disintegrated, and the provinces were annexed by the Bulgars and Byzantines. In 1034, Stefan Vojislav (the founder of the Vojislavljević dynasty) incited a rebellion and renounced Byzantine rule, becoming the Prince of Serbs, ruling from the seat at Duklja. In the early 12th century, Desa of the Vukanović dynasty wrestled the region, and it continued under the rule of the Nemanjić dynasty (1166–1371), either held by dynastic members or close associates (most often military commanders), of which was the notable Vojinović noble family. After Nikola Altomanović, the holder of a large province during the fall of the Serbian Empire, was defeated in 1373, his estates were divided between Prince Lazar Hrebeljanović of Serbia, Đurađ I Balšić of Zeta, and Ban Tvrtko I Kotromanić of Bosnia. Trebinje continued under the Bosnian crown in the hands of the Pavlović family, and from 1435 under the Kosača family. It was finally annexed in 1481 by the Ottomans and organized into the Sanjak of Herzegovina.

Simeon I the Great (Church Slavonic: цѣсар҄ь Сѷмеѡ́нъ А҃ Вели́къ; Bulgarian: цар Симеон I Велики, romanized: Simeon I Veliki [simɛˈɔn ˈpɤrvi vɛˈliki]; Greek: Συμεών Αʹ ὁ Μέγας, romanized: Sumeṓn prôtos ho Mégas) ruled over Bulgaria from 893 to 927, during the First Bulgarian Empire. Simeon's successful campaigns against the Byzantines, Magyars and Serbs led Bulgaria to its greatest territorial expansion ever, making it the most powerful state in contemporary Eastern and Southeast Europe. His reign was also a period of unmatched cultural prosperity and enlightenment later deemed the Golden Age of Bulgarian culture.

During Simeon's rule, Bulgaria spread over a territory between the Aegean, the Adriatic and the Black seas. The newly independent Bulgarian Orthodox Church became the first new patriarchate besides the Pentarchy, and Bulgarian Glagolitic and Cyrillic translations of Christian texts spread all over the Slavic world of the time. It was at the Preslav Literary School in the 890s that the Cyrillic alphabet was developed. Halfway through his reign, Simeon assumed the title of "emperor" (Tsar), having prior to that been styled "prince" (Knyaz).

The Slavs were Christianized in waves from the 7th to 12th century, though the process of replacing old Slavic religious practices began as early as the 6th century. Generally speaking, the monarchs of the South Slavs adopted Christianity in the 9th century, the East Slavs in the 10th, and the West Slavs between the 9th and 12th century. Saints Cyril and Methodius (fl. 860–885) are attributed as "Apostles to the Slavs", having introduced the Byzantine-Slavic rite (Old Slavonic liturgy) and Glagolitic alphabet, the oldest known Slavic alphabet and basis for the Early Cyrillic alphabet.

The simultaneous missionary efforts to convert the Slavs by what would later become known as the Catholic Church of Rome and the Eastern Orthodox Church of Constantinople led to a 'second point of contention between Rome and Constantinople', especially in Bulgaria (9th–10th century). This was one of many events that preceded the East–West Schism of 1054 and led to the eventual split between the Greek East and Latin West. The Slavs thus became divided between Eastern Orthodoxy and Roman Catholicism. Closely connected to the competing missionary efforts of the Roman Church and the Byzantine Church was the spread of the Latin and Cyrillic scripts in Eastern Europe. The majority of Orthodox Slavs adopted Cyrillic, while most Catholic Slavs adopted the Latin, but there were many exceptions to this general rule. In areas where both Churches were proselytising to pagan Europeans, such as the Grand Duchy of Lithuania, the Croatian Duchy and the Principality of Serbia, mixtures of languages, scripts and alphabets emerged, and the lines between Latin Catholic (Latinitas) and Cyrillic Orthodox literacy (Slavia Orthodoxa) were blurred.