Duchy of Lithuania Duchy of Lithuania Duchy of Lithuania (; ) was a state-territorial formation of ethnic Lithuanians, that existed from the 13th century until 1413. Most of the time it was a constituent part and a nucleus of the Grand Duchy of Lithuania. Other alternative names of the territorial formation, used in different periods, were Aukštaitija or Land of Lithuania (13th century), Duchy of Vilnius (14th – early 15th centuries), Lithuania Propria or simply Lithuania (in a narrow sense). The formation emerged in the central and eastern part of the present-day Lithuania, known as Aukštaitija, as the Lietuva Land (). It is
Law of Lithuania the Grand Duke of Lithuania Casimir Jagiellon with the Lithuanian Council of Lords. It is considered to be the first codified law of the Grand Duchy of Lithuania. Statutes of Lithuania, published three times (in 1529, 1566 and 1588) were the most influent legal codes of Lithuania. The third variant of the Statute was in force in the territory of Lithuania until 1840 when it got replaced by the Russian laws. However, under the rule of the Russian Empire, there were three separate civil law systems in force in Lithuania: in Suvalkija the Napoleonic Code was still applied, whereas the