I took the data from other my project. Old-styled overlay has to show borders of Russian Empire.
In 19th century Jews were noticeable minority on Belarusian lands. Unfortunately, this was changed in 20th century. After short uplift of Yiddish-speaking culture in early years of Belarusian Soviet Republic there was a number of events which drastically changed national and cultural landscape of the country: Stalin's repressions, Second World War, emerging of independent Israel.
It is a pity, that nowadays this part of our history is rather forgotten, despite BSSR was only country were Yiddish was one of official languages.