Jews are first known to have lived in Kovno as early as 1410 when they were brought forcibly as prisoners of war by the Grand Duke Vytautas. Many of those Jews were later active as traders between Kovno and Danzig (today's Gdansk, Poland). Living conditions for many Jews were squalid. In 1858, archaic living restrictions were relaxed and all but 6,000 of the city's 35,000 Jews flocked to the Old Town in search of something better. During the inter-war period Kaunas had a Jewish population of 35,000–40,000, about one quarter of the city's total population. Kaunas was a centre of Jewish learning, and the yeshiva in Slobodka (Vilijampolė) was one of Europe's most prestigious institutes of higher Jewish learning. Kaunas had a rich and varied Jewish culture. There were almost 100 Jewish organizations, 40 synagogues, many Yiddish schools, 4 Hebrew high schools, a Jewish hospital, and scores of Jewish-owned businesses. It was also an important Zionist centre. The occupation of Soviet troops was accompanied by arrests, confiscations, and the elimination of all free institutions. Jewish community organizations disappeared almost overnight. Soviet authorities confiscated the property of many Jews, while hundreds were exiled to Siberia. The Yiddish name is Kovne (קאָװנע). Kaunas has a small synagogue and congregation. Built in 1871, it is today the only remaining synagogue.