Complex sentence: Due to Eysler's Jewish background, his works were banned from being perfomed by the Nazis, leading Adolf Hitler to discover that his favourite operetta, "Die gold'ne Meisterin", was by a Jew.
Split into simpler sentences: Due to Eysler's Jewish background, his works were banned from being perfomed by the Nazis. That was when Adolf Hitler discovered that his favourite operetta, "Die gold'ne Meisterin", was by a Jew.