This is now the church of the Belarussian community in Vilnius. Vilnius is fairly close to the borders of both Belarus and Poland and has strong communities from both nations - some stretching back generations to when Vilnius was Polish. The Grand Duchy of Lithuania stretched from the Baltic to the Black Sea:
"The Grand Duchy of Lithuania was a European state from the 13th century until 1795. The state was founded by the Lithuanians, one of the polytheistic Baltic tribes from Aukštaitija. The Grand Duchy later expanded to include large portions of the former Kievan Rus' and other Slavic lands, including territory of present-day Belarus, parts of Ukraine, Poland and Russia. At its greatest extent in the 15th century, it was the largest state in Europe. It was a multi-ethnic and multi-confessional state with great diversity in languages, religion, and cultural heritage." (Wikipedia).