Lithuania proper in the context of "Lithuania Minor"

Vilnius Region is the territory in present-day Lithuania and Belarus that was originally inhabited by ethnic Baltic tribes and was a part of Lithuania proper, but came under East Slavic and Polish cultural influences over time.

The territory included Vilnius, the historical capital of the Grand Duchy of Lithuania. Lithuania, after declaring independence from the Russian Empire, claimed the Vilnius Region based on this historical legacy. Poland argued for the right of self-determination of the local Polish-speaking population. As a result, throughout the interwar period the control over the area was disputed between Poland and Lithuania. The Soviet Union recognized it as part of Lithuania in the Soviet–Lithuanian Peace Treaty, but in 1920 it was seized by Poland and became part of the short-lived puppet state of Central Lithuania, and was subsequently incorporated into the Second Polish Republic.

Mindaugas (c. 1203 – 12 September 1263) was the first known Grand Duke of Lithuania and the only crowned King of Lithuania. Little is known of his origins, early life, or rise to power; he is mentioned in a 1219 treaty as an elder duke, and in 1236 as the leader of all the Lithuanians. The contemporary and modern sources discussing his ascent mention strategic marriages along with banishment or murder of his rivals. He extended his domain into regions southeast of Lithuania proper during the 1230s and 1240s. In 1250 or 1251, during the course of internal power struggles, he was baptised as a Roman Catholic; this action enabled him to establish an alliance with the Livonian Order, a long-standing antagonist of the Lithuanians. By 1245, Mindaugas was already being referred to as "the highest king" in certain documents. During the summer of 1253, he was crowned king, ruling between 300,000 and 400,000 subjects, and got nicknamed as Mindaugas the Sapient by the Livonians.

While Mindaugas's ten-year reign as king was marked by many state-building accomplishments, his conflicts with relatives and other dukes continued. The western part of Lithuania – Samogitia – strongly resisted the alliance's rule. His gains in the southeast were challenged by the Tatars. He broke peace with the Livonian Order in 1261, possibly renouncing Christianity, and was assassinated in 1263 by his nephew Treniota and another rival, Duke Daumantas of Pskov. His three immediate successors were assassinated as well. The disorder was not resolved until Traidenis gained the title of grand duke c. 1270.

Samogitia, often known by its Lithuanian name Žemaitija (Samogitian: Žemaitėjė; see below for alternative and historical names) is one of the five cultural regions of Lithuania and formerly one of the two core administrative divisions of the Grand Duchy of Lithuania alongside Lithuania proper.

Žemaitija is located in northwestern Lithuania. Its capital city is Telšiai and the largest city is Šiauliai (located on the border between Samogitia and Aukštaitija). Throughout centuries, Samogitia developed a separate culture featuring diverse architecture, folk costumes, dances, songs, traditions, and a distinct Samogitian language.

The Volok Reform (Lithuanian: Valakų reforma; Belarusian: Валочная памера; Polish: reforma włóczna) was a 16th-century land reform in parts of the Grand Duchy of Lithuania (Lithuania proper, Duchy of Samogitia and parts of White Ruthenia). The reform was started by Grand Duchess Bona Sforza in her possessions to increase the revenues of the state treasury but soon was expanded statewide and was copied by other nobles and the Church. The reform increased effectiveness of agriculture by establishing a strict three-field system for crop rotation. The land was measured, registered in a cadastre, and divided into voloks (land unit of about 21.38 hectares (52.8 acres)). Volok became the measurement of feudal services. The reform was a success in terms of the annual state revenue that quadrupled from 20,000 to 82,000 kopas of Lithuanian groschens. In social terms, the reform and the accompanying Third Statute of Lithuania (1588), promoted development of manorialism and fully established serfdom in Lithuania which existed until the emancipation reform of 1861. The nobility was clearly separated from the peasants which severely limited social mobility.