Crimean Karaites
In 1939, using his connections with the community of Russian emigrés in Germany, he appealed to the authorities of the Ministry of Internal Affairs of the Reich with a request to examine the issue of Crimean Karaites' ethnicity. After the occupation by German troops of the areas of Eastern Europe populated by Crimean Karaites, this appellation was observed by the German administration. They involved three major historian specialists on the history of the Karaites: Zelig Kalmanovich, Meir Balaban and Yitzhak (Ignacy) Schiper. Despite the fact that all three had been before the war fierce opponents of the theory of the Turkic origin of the Crimean Karaites, they supported Shapshal's theory in order to save the European Karaites from the Holocaust. Shapshal was instrumental in the formulation of Nazi policy towards the Karaims. As Hakham of Vilnius he was infamous for his confrontations with such Jewish community figures as Zelig Kalmanovich. He was also known for having been forced (under penalty of endangering his own community) to give the Nazis a detailed list of the members of the Crimean Karaites communities of Troki and Vilnius, allowing them to easily discover and arrest Jews who had forged papers stating that they were Crimean Karaites.