Lithuania), Lithuania Proper and Ruthenia. Eastern part of Lithuania Propria For centuries, eastern and southern lands of this territory, that had direct contacts with Ruthenia and Poland, initially inhabited by ethnic Lithuanians were slowly Ruthenised, Polonised and Russified, and the Lithuanian-speaking territory shrunk. Eastern parts of Lithuania Propria suffered heavy population losses during the Deluge, and further on during the Great Northern War and following plague epidemic in 1710–1711. Subsequent immigration of Ruthenians and Poles into these territories accelerated the process. A significant push to the de-Lithuanisation ensued when Lithuania became a part of the Russian Empire, and especially, after Lithuanian language books were forbidden to print in Latin letters in 1864. The process continued at the time of Polish rule, as Lithuanian language schools and libraries were closed, and later under Soviet rule, as no Lithuanian schools were in these territories at all. Nowadays significant "islands" of Lithuanian-speaking people remain in eastern and southern parts of Lithuania proper (modern Belarus (see in Grodno Region) and Poland (see Punskas in Podlaskie Voivodeship). Many people of these territories now speaking Belarusian still refer to themselves as Lithuanians. Modern developments At the end of World War I, the Council of Lithuania declared an independent Lithuanian state re-established in the ethnic Lithuanian lands. After negotiations with Bolshevik Russia a large part of Lithuania Proper was acknowledged by Soviets as part of Lithuanian Republic by signing the Soviet-Lithuanian Treaty of 1920. Some of these territories were also claimed by Second Republic of Poland. This led to series of military conflicts and eventually to war. In 1943, Antanas Smetona (in exile at the time) began working on a study "Lithuania Propria". The book was dedicated to the history of Lithuanian lands before Polonisation, Russification, and Germanisation hoping that it would help to substantiate a claim to unreturned territories in a peace conference after World War II. His work was left unfinished, and for a long time was available only as a manuscript and was virtually unknown. Currently the Republic of Lithuania has no territorial claims. See also Duchy of Lithuania Bruno of Querfurt Ethnographic Lithuania Lithuanians in Belarus Notes a. In other languages: , or ; or ; , Lite. References Sources Historical regions in Lithuania Metropolitan or continental parts of states