 Following the Nazi / Soviet invasion of Poland , Pius XII 's Summi Pontificatus called for the sympathy of the whole world towards Poland , where " the blood of countless human beings , even noncombatants " was being spilled . Pius never publicly condemned the Nazi massacre of 1 @,@ 800 @,@ 000 – 1 @,@ 900 @,@ 000 Poles , overwhelmingly Roman Catholic ( including 2 @,@ 935 members of the Catholic clergy ) , In late 1942 , Pius XII advised German and Hungarian bishops to speak out against the massacres on the Eastern Front . In his 1942 Christmas Eve message , he expressed concern for " those hundreds of thousands , who ... sometimes only by reason of their nationality or race , are marked down for death or progressive extinction . On 7 April 1943 , Msgr. Tardini , one of Pius XII 's closest advisors , advised Pius XII that it would be politically advantageous after the war to take steps to help Slovak Jews . 
