According to the Austrian census of 1910 the town had 18,568 inhabitants . The census asked people for their native language : 15,144 ( 84.3 % ) were German-speaking , 2,568 ( 14.3 % ) were Polish-speaking and 136 ( 0.7 % ) were Czech-speaking . Jews were not allowed to declare Yiddish , and most of them thus declared German as their native language . The most populous religious groups were Roman Catholics with 10,378 ( 55.9 % ) , followed by Protestants with 4,955 ( 26.7 % ) and the Jews with 3,024 ( 16.3 % ) . The vast majority of the Jews were exterminated by Nazis during World War II , and the German population was expelled by the Soviets after the war under the terms demanded by Stalin at the Potsdam Conference
Potsdam Conference
Potsdam Conference
Bielsko