Thank you. What is of interest is that Rosenzweig makes the incredible assertion that Mahler was opposed to Wagner and Bayreuth, because it represented pre-WWI Prussian Imperialism. I think that's quite a stretch and I'm curious to read how he supports that supposition.
For one thing, Bayreuth is technically in northern Bavaria. Second, Wagner had little to do with northern German affairs. Wagner may have been both an anti-Semite and pan-German, but that doesn't mean that he carried a pro-Prussian agenda. Maybe that's splitting hairs, but there's no denying that Mahler was among the foremast conductors of Wagner's dramas in those days. Yes, I get it that Cosima was something of an adversary to Mahler. But that doesn't mean that Mahler harbored any grudge against Wagner himself. All the evidence seems to point to just the opposite.