Despite the furor over the Frederick book , and not having written a formal '' Habilitationsschrift '' ( second thesis to qualify for a professorial appointment ) , Kantorowicz received an ( honorary ) professorship at the University of Frankfurt in 1930 . By 1933 , however , Kantorowicz had to cease giving lectures due to increasing pressure on Jewish academics under the new Nazi regime . After taking several leaves of absence , he was finally granted an early retirement with a pension in 1935 . He remained in Germany until 1938 , when after the Kristallnacht riots it became clear that the situation for even assimilated Jews such as himself was no longer tenable . He accepted a teaching position for a short time at Oxford before taking up a lectureship at the University of California - Berkeley in 1939 . After several years , Kantorowicz was able to secure a permanent professorship , but in 1950 , he famously resigned in protest when the UC Regents demanded that all continuing faculty sign a loyalty oath disavowing affiliation with any politically subversive movements . Kantorowicz insisted he was no leftist and pointed to his role in an anti-communist militia as a young university student , but nonetheless objected on principle to an instrument which he viewed as a blatant infringement on academic freedom and freedom of conscience more generally . During the controversy in Berkeley , two eminent German émigré medievalists working in Princeton , Theodore Mommsen ( grandson of the great classical historian ) and the art historian Erwin Panofsky , persuaded J. Robert Oppenheimer , director of the prestigious Institute for Advanced Study , to appoint Kantorowicz to the Institute 's faculty of Historical Studies . Kantorowicz accepted and moved to Princeton , where he remained for the rest of his career
Kristallnacht
Kristallnacht
Ernst Kantorowicz