Grand Duchy of Lithuania in the context of "Smolensk"

A political union is a type of political entity which is composed of, or created from, smaller polities or the process which achieves this. These smaller polities are usually called federated states and federal territories in a federal government; they are called prefectures, regions, or provinces in the case of a centralised government. This form of government may be created through voluntary and mutual cession and is described as unionism by its constituent members and proponents. In other cases, it may arise from political unification, characterised by coercion and conquest. The unification of separate states which, in the past, had together constituted a single entity is known as reunification. Unlike a personal union or real union, the individual constituent entities may have devolution of powers but are subordinate to a central government or coordinated in some sort of organization. In a federalised system, the constituent entities usually have internal autonomy, for example in the setup of police departments, and share power with the federal government, for whom external sovereignty, military forces, and foreign affairs are usually reserved. The union is recognised internationally as a single political entity. A political union may also be called a legislative union or state union.A union may be effected in many forms, broadly categorized as:

• Incorporating union
• Incorporating annexation
• Federal union
• Federative annexation
• Mixed unions

Ukraine is a country in Eastern Europe. It is the second-largest country in Europe after Russia, which borders it to the east and northeast. Ukraine also borders Belarus to the north; Poland and Slovakia to the west; Hungary, Romania and Moldova to the southwest; and the Black Sea and the Sea of Azov to the south and southeast. Kyiv is the nation's capital and largest city, followed by Kharkiv, Odesa, and Dnipro. Ukraine's official language is Ukrainian.

Humans have inhabited Ukraine since 32,000 BC. During the Middle Ages, it was the site of early Slavic expansion and later became a key centre of East Slavic culture under the state of Kievan Rus', which emerged in the 9th century. Kievan Rus' became the largest and most powerful realm in Europe in the 10th and 11th centuries, but gradually disintegrated into rival regional powers before being destroyed by the Mongols in the 13th century. For the next 600 years the area was contested, divided, and ruled by a variety of external powers, including the Grand Duchy of Lithuania, the Kingdom of Poland, the Polish–Lithuanian Commonwealth, the Austrian Empire, the Ottoman Empire, and the Tsardom of Russia.

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.

The Crown of the Kingdom of Poland (Polish: Korona Królestwa Polskiego; Latin: Corona Regni Poloniae) was a political and legal concept formed in the 14th century in the Kingdom of Poland, assuming unity, indivisibility and continuity of the state. Under this idea, the state was no longer seen as the patrimonial property of the monarch or dynasty, but became a common good of the political community of the kingdom. This notion allowed the state to maintain stability even during periods of interregnum and paved the way for a unique political system in Poland, characterized by a noble-based parliament and the free election of the monarch. Additionally, the concept of the Crown extended beyond existing borders, asserting that previously lost territories still rightfully belonged to it. The term Crown of the Kingdom of Poland also referred to all the lands under the rule of the Polish king. This meaning became especially significant after the union with the Grand Duchy of Lithuania, when it began to be commonly used to denote the Polish part of the joint Polish-Lithuanian Commonwealth.

The idea of the Crown in Central Europe first appeared in Bohemia and Hungary, from where the model was taken by kings Ladislaus the Short and Casimir III the Great to strengthen their power. During the reign of Louis the Great in Poland, who spent most of his time in Hungary, as well as during the interregnum following his death and the regency during the minority of his daughter Jadwiga, the idea was adopted by the lords of the kingdom to emphasize their own role as co-responsible for the state.

The Polish–Lithuanian Commonwealth, also referred to as Poland–Lithuania or the First Polish Republic (Polish: I Rzeczpospolita), was a federative real union between the Kingdom of Poland and the Grand Duchy of Lithuania, existing from 1569 to 1795. This state was among the largest, most populated countries of 16th- to 18th-century Europe. At its peak in the early 17th century, the Commonwealth spanned approximately 1,000,000 km (390,000 sq mi) and supported a multi-ethnic population of around 12 million as of 1618. The official languages of the Commonwealth were Polish and Latin, with Catholicism as the state religion.

The Union of Lublin established the Commonwealth as a single entity on 1 July 1569. The two nations had previously been in a personal union since the Krewo Agreement of 1385 (Polish–Lithuanian union) and the subsequent marriage of Queen Jadwiga of Poland to Grand Duke Jogaila of Lithuania, who was crowned as Władysław II Jagiełło, jure uxoris King of Poland. Their descendant, Sigismund II Augustus, enforced the merger to strengthen frontiers of his dominion and maintain unity. As he remained childless, his death in 1572 marked the end of the Jagiellonian dynasty. It introduced an elective monarchy, whereupon members of domestic noble families or external dynasties were elected to the throne for life.

Real union is a union of two or more states, which share some state institutions in contrast to personal unions; however, they are not as unified as states in a political union. It is a development from personal union and has historically been limited to monarchies.

Unlike personal unions, real unions almost exclusively led to a reduction of sovereignty for the politically weaker constituent. That was the case with Lithuania and Norway, which came under the influence of stronger neighbors, Poland and Denmark respectively, with which each of them had shared a personal union previously.

The Polish–Lithuanian union was a relationship created by a series of acts and alliances between the Crown of the Kingdom of Poland and the Grand Duchy of Lithuania that lasted for prolonged periods of time from 1385 and led to the creation of the Polish–Lithuanian Commonwealth, or the "Republic of the Two Nations", in 1569, which ended in 1795 with the Third Partition.

Belarus, officially the Republic of Belarus, is a landlocked country in Eastern Europe. It is bordered by Russia to the east and northeast, Ukraine to the south, Poland to the west, and Lithuania and Latvia to the northwest. Belarus spans an area of 207,600 square kilometres (80,200 sq mi) with a population of 9.1 million. The country has a hemiboreal climate and is administratively divided into six regions. Minsk is the capital and largest city; it is administered separately as a city with special status.

For most of the medieval period, the lands of modern-day Belarus was ruled by independent city-states such as the Principality of Polotsk. Around 1300 these lands came fully under the Grand Duchy of Lithuania and subsequently by the Polish–Lithuanian Commonwealth; this period lasted for 500 years until the 1792-1795 partitions of Poland-Lithuania placed Belarus within the Russian Empire for the first time. In the aftermath of the Russian Revolution in 1917, different states arose competing for legitimacy amid the Civil War, ultimately ending in the rise of the Byelorussian SSR, which became a founding constituent republic of the Soviet Union in 1922. After the Polish-Soviet War (1918–1921), Belarus lost almost half of its territory to Poland. Much of the borders of Belarus took their modern shape in 1939, when some lands of the Second Polish Republic were reintegrated into it after the Soviet invasion of Poland, and were finalized after World War II. During World War II, military operations devastated Belarus, which lost about a quarter of its population and half of its economic resources. In 1945, the Byelorussian SSR became a founding member of the United Nations, along with the Soviet Union. The republic was home to a widespread and diverse anti-Nazi insurgent movement which dominated politics until well into the 1970s, overseeing Belarus's transformation from an agrarian to an industrial economy.

A statute is a law or formal written enactment of a legislature. Statutes typically declare, command or prohibit something. Statutes are distinguished from court law and unwritten law (also known as common law) in that they are the expressed will of a legislative body, whether that be on the behalf of a country, state or province, county, municipality, or so on. They are also distinguished from secondary legislation, or regulations, that are issued by an executive body under authority granted by a statute. Depending on the legal system, a statute may also be referred to as an "act."