Ukraine in the context of Cossack uprisings

The Black Sea is a marginal sea lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Romania, Russia, Turkey, and Ukraine. The Black Sea is supplied by major rivers, principally the Danube, Dnieper and Dniester. Consequently, while six countries have a coastline on the sea, its drainage basin includes parts of 24 countries in Europe.

The Black Sea, not including the Sea of Azov, covers 436,400 km (168,500 sq mi), has a maximum depth of 2,212 m (7,257 ft), and a volume of 547,000 km (131,000 cu mi).Most of its coasts ascend rapidly.These rises are the Pontic Mountains to the south, bar the southwest-facing peninsulas, the Caucasus Mountains to the east, and the Crimean Mountains to the mid-north.In the west, the coast is generally small floodplains below foothills such as the Strandzha; Cape Emine, a dwindling of the east end of the Balkan Mountains; and the Dobruja Plateau considerably farther north. The longest east–west extent is about 1,175 km (730 mi). Important cities along the coast include (clockwise from the Bosporus) the northern suburbs of Istanbul, Burgas, Varna, Constanța, Odesa, Yalta, Kerch, Yevpatoria, Sevastopol, Novorossiysk, Sochi, Poti, Batumi, Rize, Trabzon, Ordu, Simferopol, Samsun and Zonguldak.

The European single market, also known as the European internal market or the European common market, is the single market comprising mainly the 27 member states of the European Union (EU). With certain exceptions, it also comprises Iceland, Liechtenstein, Norway (through the Agreement on the European Economic Area), and Switzerland (through sectoral treaties). The single market seeks to guarantee the free movement of goods, capital, services, and people, known collectively as the four freedoms of the European Union. This is achieved through common rules and standards that all participating states are legally committed to follow.

Any potential EU accession candidates are required to make association agreements with the EU during the negotiation, which must be implemented prior to accession. In addition, through three individual agreements on a Deep and Comprehensive Free Trade Area (DCFTA) with the EU, Georgia, Moldova, and Ukraine have also been granted limited access to the single market in selected sectors. Turkey has access to the free movement of some goods via its membership in the European Union–Turkey Customs Union. The United Kingdom left the European single market on 31 December 2020. An agreement was reached between the UK Government and European Commission to align Northern Ireland on rules for goods with the European single market, to maintain an open border on the island of Ireland.

Crimea (/kraɪˈmiːə/ kry-MEE-ə) is a peninsula in Eastern Europe, on the northern coast of the Black Sea, almost entirely surrounded by the Black Sea and the smaller Sea of Azov. The Isthmus of Perekop connects the peninsula to Kherson Oblast in mainland Ukraine. To the east, the Crimean Bridge, constructed in 2018, spans the Strait of Kerch, linking the peninsula with Krasnodar Krai in Russia. The Arabat Spit, located to the northeast, is a narrow strip of land that separates the Syvash lagoons from the Sea of Azov. Across the Black Sea to the west lies Romania and to the south is Turkey. The population is 2.4 million, and the largest city is Sevastopol. The region, internationally recognised as part of Ukraine, has been under Russian occupation since 2014.

Called the Tauric Peninsula until the early modern period, Crimea has historically been at the boundary between the classical world and the steppe. Greeks colonised its southern fringe and were absorbed by the Roman and Byzantine Empires and successor states while remaining culturally Greek. Some cities became trading colonies of Genoa, until conquered by the Ottoman Empire. Throughout this time the interior was occupied by a changing cast of steppe nomads, coming under the control of the Golden Horde in the 13th century from which the Crimean Khanate emerged as a successor state. In the 15th century, the Khanate became a dependency of the Ottoman Empire. Lands controlled by Russia and Poland-Lithuania were often the target of slave raids during this period. In 1783, after the Russo-Turkish War (1768–1774), the Russian Empire annexed Crimea. Crimea's strategic position led to the 1854 Crimean War and many short lived regimes following the 1917 Russian Revolution. When the Bolsheviks secured Crimea, it became an autonomous soviet republic within the Russian Soviet Federative Socialist Republic. It was occupied by Germany during World War II. When the Soviets retook it in 1944, Crimean Tatars were ethnically cleansed and deported under the orders of Joseph Stalin, in what has been described as a cultural genocide. Crimea was downgraded to an oblast in 1945. In 1954, the USSR transferred the oblast to the Ukrainian Soviet Socialist Republic on the 300th anniversary of the Pereyaslav Treaty in 1654.

East Thrace or Eastern Thrace, also known as Turkish Thrace or European Turkey, is the part of Turkey that is geographically in Southeast Europe. Turkish Thrace accounts for 3.03% of Turkey's land area and 15% of its population. The largest city is Istanbul, which straddles the Bosporus between Europe and Asia. East Thrace is of historic importance as it is next to a major sea trade corridor and constitutes what remains of the once-vast Ottoman region of Rumelia. It is currently also of specific geostrategic importance because the sea corridor, which includes two narrow straits, provides access to the Mediterranean Sea from the Black Sea for the navies of five countries: Russia, Ukraine, Romania, Bulgaria, and Georgia. The region also serves as a future connector of existing Turkish, Bulgarian, and Greek high-speed rail networks.Due to the guest worker agreement with Turkey and Germany, some Turks in Germany originally come from Eastern Thrace, mostly from the Kırklareli Province.

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.

Old Great Bulgaria (Medieval Greek: Παλαιά Μεγάλη Βουλγαρία, Palaiá Megálē Voulgaría), also often known by the Latin names Magna Bulgaria and Patria Onoguria ("Onogur land"), was a 7th-century Turkic nomadic empire formed by the Onogur-Bulgars on the western Pontic–Caspian steppe (modern southern Ukraine and southwest Russia). Great Bulgaria was originally centered between the Dniester and lower Volga.

The original capital was Phanagoria on the Taman Peninsula between the Black and Azov seas. In the mid-7th century, Great Bulgaria expanded west to include Avar territory and was centered on Poltava. During the late 7th century, however, an Avar-Slavic alliance in the west, and Khazars in the east, defeated the Bulgars, and Great Bulgaria disintegrated. Successor states are the First Bulgarian Empire and Volga Bulgaria.

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.

The East European Plain (also called the Russian Plain, or historically the Sarmatic Plain) is a vast interior plain extending east of the North European Plain, and comprising several plateaus stretching roughly from 25 degrees longitude eastward. It includes Volhynian-Podolian Upland on its westernmost fringe, the Central Russian Upland, and, on the eastern border, encompasses the Volga Upland. The plain includes also a series of major river basins such as the Dnieper Lowland, the Oka–Don Lowland, and the Volga Basin. At the southeastern point of the East European Plain are the Caucasus and Crimean mountain ranges. Together with the North European Plain (covering much of Belgium, the Netherlands, Denmark, Germany and Poland), and covering the Baltic states (Estonia, Latvia and Lithuania), European Russia, Belarus, Ukraine, Moldova, southeastern Romania, and, at its southernmost point, the Danubian Plain in Northern Bulgaria (including Ludogorie and Southern Dobruja), it constitutes the majority of the Great European Plain (European Plain), the greatest mountain-free part of the European landscape. The plain spans approximately 4,000,000 km (2,000,000 sq mi) and averages about 170 m (560 ft) in elevation. The highest point of the plain (480 metres (1,574.8 ft)) is in the Bugulma-Belebey Upland, in the Eastern part of the plain, in the elevated area by the Ural Mountains (priyralie).

The Dniester (/ˈniːstər/ NEE-stər) is a transboundary river in Eastern Europe. It runs first through Ukraine and then through Moldova (from which it more or less separates the breakaway territory of Transnistria), finally discharging into the Black Sea on Ukrainian territory again.

The Sea of Azov is an inland shelf sea in Eastern Europe connected to the Black Sea by the narrow (about 4 km (2.5 mi)) Strait of Kerch, and sometimes regarded as a northern extension of the Black Sea. The sea is bounded by Russia on the east, and by Ukraine on the northwest and southwest (the parts of Ukraine bordering the sea are currently under Russian occupation). It is an important access route for Central Asia, from the Caspian Sea via the Volga–Don Canal.

The sea is largely affected by the inflow of the Don, Kuban, and other rivers, which bring sand, silt, and shells, which in turn form numerous bays, limans, and narrow spits. Because of these deposits, the sea bottom is relatively smooth and flat, with the depth gradually increasing toward the middle. Because of the river inflow, water in the sea has low salinity and a high amount of biomass (such as green algae) that affects the water colour. Abundant plankton result in unusually high fish productivity. The sea shores and spits are low; they are rich in vegetation and bird colonies. The Sea of Azov is the shallowest sea in the world, with the depth varying between 0.9 and 14 metres (3 and 46 ft). There is a constant outflow of water from the Sea of Azov to the Black Sea.

Odesa, also spelled Odessa, is the third most populous city and municipality in Ukraine and a major seaport and transport hub located in the south-west of the country, on the northwestern shore of the Black Sea. The city is also the administrative centre of the Odesa Raion and Odesa Oblast, as well as a multiethnic cultural centre. As of January 2021, Odesa's population was approximately 1,010,537. On 25 January 2023, its historic city centre was declared a World Heritage Site and added to the List of World Heritage in Danger by the UNESCO World Heritage Committee in recognition of its multiculturality and 19th-century urban planning. The declaration was made in response to the bombing of Odesa during the Russian invasion of Ukraine, which has damaged or destroyed buildings across the city.

In classical antiquity a large Greek settlement existed at its location no later than the middle of the 6th century BC. It has been researched as a possible site of the ancient Greek settlement of Histria. The first chronicle mention of the Slavic settlement-port of Kotsiubijiv, which was part of the Grand Duchy of Lithuania, dates back to 1415, when a ship was sent from here to Constantinople by sea. After the Grand Duchy lost control, the port and its surroundings became part of the domain of the Ottoman Empire in 1529, under the name Hacibey, and remained in it until the Ottomans' defeat in the Russo-Turkish War (1787–1792). In 1794, a decree of the Russian empress Catherine II was issued to establish a navy harbor and trading place in Khadjibey, which was named Odessa soon after. From 1819 to 1858, Odesa was a free port. During the Soviet period, it was an important trading port and a naval base. During the 19th century, Odesa was the fourth largest city of the Russian Empire, after Moscow, Saint Petersburg and Warsaw. Its historical architecture is more Mediterranean than Russian, having been heavily influenced by French and Italian styles. Some buildings are built in a mixture of different styles, including Art Nouveau, Renaissance and Classicist.

Yalta (Ukrainian and Russian: Ялта) is a resort city on the south coast of the Crimean Peninsula surrounded by the Black Sea. It serves as the administrative center of Yalta Municipality, one of the regions within Crimea. Yalta, along with the rest of Crimea, is internationally recognised as part of Ukraine, and is considered part of the Autonomous Republic of Crimea. However, it is controlled de facto by Russia, which annexed Crimea in 2014 and regards the town as part of the Republic of Crimea. According to the most recent census, its population was 76,746 (2014 Census).

The city is located on the site of the ancient Greek colony of Yalita (Greek: Γιαλός, romanized: Gialós [ʝaˈlos̠]). It is said to have been founded by Greek settlers who were looking for a safe shore on which to land. It is situated on a deep bay facing south towards the Black Sea, surrounded by the mountain range Ai-Petri. It has a humid subtropical climate and is surrounded by numerous vineyards and orchards.

Sevastopol (/ˌsɛvəˈstoʊpəl, sɪˈvæstəpoʊl/ SEV-ə-STOH-pəl, siv-AST-ə-pohl), sometimes written Sebastopol, is the largest city in Crimea and a major port on the Black Sea. Due to its strategic location and the navigability of the city's harbours, Sevastopol has been an important port and naval base throughout its history. Since the city's founding in 1783, it has been a major base for Russia's Black Sea Fleet. During the Cold War of the 20th century, it was a closed city. The total administrative area is 864 square kilometres (334 sq mi) and includes a significant amount of rural land. The urban population, largely concentrated around Sevastopol Bay, is 479,394, and the total population is 547,820.

Sevastopol, along with the rest of Crimea, is internationally recognised as part of Ukraine, and under the Ukrainian legal framework, it is administratively one of two cities with special status (the other being Kyiv). However, it has been occupied by Russia since 27 February 2014, before Russia annexed Crimea on 18 March 2014 and gave it the status of a federal city of Russia. Both Ukraine and Russia consider the city administratively separate from the Autonomous Republic of Crimea and the Republic of Crimea, respectively. The city's population has an ethnic Russian majority and a substantial minority of Ukrainians and Crimean Tatars.

Simferopol (/ˌsɪmfəˈroʊpəl/ SIM-fər-OH-pəl), also known as Aqmescit, is the second-largest city on the Crimean Peninsula. The city, along with the rest of Crimea, is internationally recognized as part of Ukraine, but controlled by Russia. It is considered the capital of the Autonomous Republic of Crimea.

Since 2014 it has been under the de facto control of Russia, which annexed Crimea that year and regards Simferopol as the capital of the Republic of Crimea.

Eastern Europe is a subregion of the European continent. As a largely ambiguous term, it has a wide range of geopolitical, geographical, ethnic, cultural and socio-economic connotations. Its eastern boundary is marked by the Ural Mountains, and its western boundary is defined in various ways. Narrow definitions, in which Central and Southeast Europe are counted as separate regions, include Belarus, Russia and Ukraine. In contrast, broader definitions include Moldova and Romania, but also some or all of the Balkans, the Baltic states, the Caucasus, and the Visegrád group. In Eastern Europe, Russia is the largest and most populous country.

The region represents a significant part of European culture; the main socio-cultural characteristics of Eastern Europe have historically largely been defined by the traditions of the Slavs, as well as by the influence of Eastern Christianity as it developed through the Eastern Roman Empire and the Ottoman Empire. Another definition was created by the Cold War, as Europe was ideologically divided by the Iron Curtain, with "Eastern Europe" being synonymous with communist states constituting the Eastern Bloc under the influence of the Soviet Union.

The Grand Duchy of Lithuania was a sovereign state in northeastern Europe that existed from the 13th century, succeeding the Kingdom of Lithuania, to the late 18th century, when the territory was suppressed during the 1795 partitions of Poland–Lithuania. The state was founded by Lithuanians, who were at the time a polytheistic nation of several united Baltic tribes from Aukštaitija. By 1440 the grand duchy had become the largest European state, controlling an area from the Baltic Sea in the north to the Black Sea in the south.

The grand duchy expanded to include large portions of the former Kievan Rus' and other neighbouring states, including what is now Belarus, Lithuania, most of Ukraine as well as parts of Latvia, Moldova, Poland and Russia. At its greatest extent, in the 15th century, it was the largest state in Europe. It was a multi-ethnic and multiconfessional state, with great diversity in languages, religion, and cultural heritage.

The Deep and Comprehensive Free Trade Areas (DCFTA) are three free trade areas established between the European Union, and Georgia, Moldova, and Ukraine respectively. The DCFTAs are part of each country's EU Association Agreement. They allow Georgia, Moldova, and Ukraine access to the European Single Market in selected sectors and grant EU investors in those sectors the same regulatory environment in the associated country as in the EU. The agreements with Moldova and Georgia have been ratified and officially entered into force in July 2016, although parts of them were already provisionally applied. The agreement with Ukraine was provisionally applied since 1 January 2016 and formally entered into force on 1 September 2017.

Unlike standard free trade areas, the DCFTA is aimed to offer the associated country the "four freedoms" of the EU Single Market: free movement of goods, services, capital, and people. Movement of people however, is in form of visa-free regime for short stay travel, while movement of workers remains within the remit of the EU Member States. The DCFTA is an "example of the integration of a Non-EEA-Member into the EU Single Market".

Moldova, officially the Republic of Moldova, is a landlocked country in Eastern Europe, with an area of 33,843 km (13,067 sq mi) and a population of 2.38 million. Moldova is bordered by Romania to the west and Ukraine to the north, east, and south. The unrecognised breakaway state of Transnistria lies across the Dniester river on the country's eastern border with Ukraine. Moldova is a unitary parliamentary representative democratic republic with its capital in Chișinău, the country's largest city and main cultural and commercial centre.

Most of Moldovan territory was a part of the Principality of Moldavia from the 14th century until 1812, when it was ceded to the Russian Empire by the Ottoman Empire (to which Moldavia was a vassal state) and became known as Bessarabia. In 1856, southern Bessarabia was returned to Moldavia, which three years later united with Wallachia to form Romania. Still, Russian rule was restored over the entire region in 1878. During the 1917 Russian Revolution, Bessarabia briefly became an autonomous state within the Russian Republic. In February 1918, it declared independence and then integrated into Romania later that year following a vote of its assembly. The decision was disputed by Soviet Russia, which in 1924 established, within the Ukrainian SSR, a so-called Moldavian autonomous republic on partially Moldovan-inhabited territories to the east of Bessarabia. In 1940, as a consequence of the Molotov–Ribbentrop Pact, Romania was compelled to cede Bessarabia and Northern Bukovina to the Soviet Union, leading to the creation of the Moldavian Soviet Socialist Republic (Moldavian SSR).

The Germanic peoples were tribal groups who lived in Northern Europe during Classical antiquity and the Early Middle Ages. In modern scholarship, they typically include not only the Roman-era Germani who lived in both Germania and parts of the Roman Empire, but also all Germanic speaking peoples from this era, irrespective of where they lived, most notably the Goths. Another term, ancient Germans, is considered problematic by many scholars because it suggests identity with present-day Germans. Although the first Roman descriptions of Germani involved tribes west of the Rhine, their homeland of Germania was portrayed as stretching east of the Rhine, to southern Scandinavia and the Vistula in the east, and to the upper Danube in the south. Other Germanic speakers, such as the Bastarnae and Goths, lived further east in what is now Moldova and Ukraine. The term Germani is generally only used to refer to historical peoples from the 1st to 4th centuries CE.

Different academic disciplines have their own definitions of what makes someone or something "Germanic". Some scholars call for the term's total abandonment as a modern construct, since lumping "Germanic peoples" together implies a common group identity for which there is little evidence. Other scholars have defended the term's continued use and argue that a common Germanic language allows one to speak of "Germanic peoples", regardless of whether these ancient and medieval peoples saw themselves as having a common identity. Scholars generally agree that it is possible to refer to Germanic languages from about 500 BCE. Archaeologists usually associate the earliest clearly identifiable Germanic speaking peoples with the Jastorf culture of the Pre-Roman Iron Age in central and northern Germany and southern Denmark from the 6th to 1st centuries BCE. This culture existed around the same time that the First Germanic Consonant Shift is theorized to have occurred, leading to recognizably Germanic languages. Germanic languages expanded south, east, and west, coming into contact with Celtic, Iranic, Baltic, and Slavic peoples before they were noted by the Romans.