David Bernstein blogs on a lecture by Matthias Kuentzel, which details the curious entrance of anti-Semitism (in its current virulent form):

. . . while there was always anti-Jewish sentiment in the Muslim world, it also was based on the notion of Jews as an inferior group that Mohammed had defeated militarily. Anti-Semitic visions of powerful Jews being behind the world's problems, and plotting to control the world, found most prominently in the Hamas charter, entered the Muslim world via the Muslim Brotherhood, who in turn took those ideas from the Nazis, which spent significant effort and money propagating them in the Middle East. This all started well before the creation of the State of Israel, belying the notion that the Israel-Palestinian conflict caused modern Muslim anti-Semitism.