Less well-known, however, was the fact that the "Aryan" girl it claimed to show was actually Jewish.
A. But few people were aware that the girl who was claimed to be "Aryan" was, in fact, Jewish.
B. The "Aryan" girl was not very well-known because she was claimed to be Jewish.
It was the time of surging anti-Semitism in Berlin.
A. Berlin was growing very fast during the time of anti-Semitism
B. Anti-Semitism spread quickly in Berlin at that time.