Nazi antisemitism embraced pseudoscientific racial principles, but ancient antipathies between Christianity and Judaism contributed to European antisemitism. The church rescued thousands of Jews, however, by issuing false documents, lobbying Axis officials and hiding Jews in monasteries, convents, schools, the Vatican and the papal residence at Castel Gandolfo. Although Pius XII's role during this period is contested, the Reich Main Security Office called him a "mouthpiece" of the Jews and his first encyclical (Summi Pontificatus) called the invasion of Poland an "hour of darkness."