Wikipedia
Judenzählung ( German for " Jewish census") was a measure instituted by the German Military High Command in October 1916, during the upheaval of World War I. Designed to confirm accusations of the lack of patriotism among German Jews, the census disproved the charges, but its results were not made public. However, its figures were leaked out, being published in an antisemitic brochure. The Jewish authorities, who themselves had compiled statistics which considerably exceeded the figures in the brochure, were not only denied access to the government archives but also informed by the Republican Minister of Defense that the contents of the antisemitic brochure were correct. In the atmosphere of growing antisemitism, many German Jews saw "the Great War" as an opportunity to prove their commitment to the German homeland.