Temporary capital of Lithuania during the invasion of Poland, to Lithuania according to the Soviet–Lithuanian Mutual Assistance Treaty. Since then Vilnius has been the capital of the Lithuanian SSR and then independent Lithuania. Lithuania refused to have diplomatic relations between Poland and Lithuania until the ultimatum of 1938. Railroad traffic, telegraph lines or even mail could not cross the Polish–Lithuanian border. Lithuania continued to declare Vilnius as its capital in all official documents, including the constitution. Since the city was controlled by Poland, all Lithuanian authorities were transferred to the city of Kaunas, which became the seat of the government. To reconcile reality with
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