This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Nazi Germany's occupation of Poland, beginning in 1939, murdered three million Polish Jews by the war's end in 1945, roughly ninety percent of the community that had stood at the center of world Jewish life for four centuries, and made up half of all Polish deaths in the war. The killing fell on a population the Statute of Kalisz had first given legal footing in 1264 and that had grown, over the centuries since, into the largest Jewish community anywhere in the world.
Roughly two hundred thousand survivors registered with the Central Committee of Polish Jews after liberation, more than half of them people who had survived the war inside the Soviet Union rather than in occupied Poland itself. The organised community life that charter had made possible did not recover from what the occupation had done to it, and Poland's Jewish population has stood at a small fraction of its former size ever since.
What this changed for Judaism's spread was the near total destruction, in six years, of a community that four centuries of settlement had built into the demographic center of the world's Jewish diaspora. Where the Statute of Kalisz once drew roughly three quarters of the world's Jews to Poland, the occupation left survival itself dependent on distance from occupied Poland, on refuge inside the Soviet Union rather than protection within Poland's own borders.