The life of Julian Unszlicht (1883–1953) illustrates the case and process of the assimilation of Polish Jews. However, Unszlicht’s case is special as it shows that holding anti-Semitic views, which were to be a ticket to a Catholic society, guaranteed neither putting the roots down permanently nor gaining a new identity. The biography of a priest-convert allows to look closer at the processes of effacement and convergence of anti-Jewish rhetoric. The modern one, of the turn of 19th and 20th centuries, with Catholic anti-Judaism, which was constantly excused by religious reasons and at the same time, it often spread to the ethnic-racial mental grounds. Contrary to common definitions and distinctions, those two ways of thinking perfectly complemented and strengthened each other, both living using the other’s reasoning. The Holocaust added a tragic punch line to the embroiled story of the priest-convert.