Complex sentence: He published writings such as "The crime of Freemasonry, Judaism, Jesuitism, German Christianity" (1921), the theory of Jewish/Masonic conspiracy, that it was bent on undermining the existence of other nations.
Split into simpler sentences: He published writings such as "The crime of Freemasonry, Judaism, Jesuitism, German Christianity" (1921). His theme was the theory of Jewish/Masonic conspiracy, that it was bent on undermining the existence of other nations.