[13] Tomas Baranauskas suggests[14] that Lithuania proper was around Ašmena area, ethnic Lithuanian lands in modern Belarus.[citation needed] Already during the Grand Duchy times, Lithuania proper was a term designated to land where Lithuanians live.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.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.[25] 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.