The Proto-Balto-Slavic languages branched off directly from Proto-Indo-European, then sub-branched into Proto-Baltic and Proto-Slavic.Proto-Baltic branched off into Proto-West Baltic and Proto-East Baltic. According to some glottochronological speculations, the Eastern Baltic languages split from the Western Baltic ones between AD 400 and 600.At a minimum, transitional dialects existed until the 14th or 15th century and perhaps as late as the 17th century.Also, the 13th- and 14th-century occupation of the western part of the Daugava basin (closely coinciding with the territory of modern Latvia) by the German Sword Brethren had a significant influence on the languages' independent development.In 1864, following the January Uprising, Mikhail Muravyov, the Russian Governor General of Lithuania, banned the language in education and publishing and barred use of the Latin alphabet altogether, although books printed in Lithuanian continued to be printed across the border in East Prussia and in the United States.Brought into the country by book smugglers despite the threat of stiff prison sentences, they helped fuel a growing nationalist sentiment that finally led to the lifting of the ban in 1904.As a Baltic language, Lithuanian is closely related to neighbouring Latvian and more distantly to Slavic, Germanic and other Indo-European languages. Lithuanian is often said to be the most conservative living Indo-European language, retaining features of Proto-Indo-European now lost in other languages.The earliest known Lithuanian glosses (~1520–1530) written in the margins of Johannes Herolt book Liber Discipuli de eruditione Christifidelium.
During the Soviet era (see History of Lithuania), it was used in official discourse along with Russian, which, as the official language of the USSR, took precedence over Lithuanian.
His proposal for Standard Lithuanian was based on his native Western Aukštaitijan dialect with some features of the eastern Prussian Lithuanians' dialect spoken in Lithuania Minor.