Kristallnacht cemented the Pfeffers ' decision to leave Berlin ; they fled to Amsterdam in December 1938 . They were there for two years before the German invasion , and subsequent anti-Jewish laws prohibiting cohabitation of Jews and non-Jews forced them to officially separate and register under different addresses . After establishing a dental practice in Amsterdam 's Rivierenbuurt , Pfeffer became acquainted with the Van Pels and Frank families . Miep Gies met Pfeffer at one of the Franks ' house parties and became a patient in his dental practice
Kristallnacht
Kristallnacht
Fritz Pfeffer