Swarowsky conducted Mahlers 3rd Symphony for the composers 100th birthday in 1960, and also met again
Alma Mahler, who came to Vienna specifically for that occasion. They knew each other since the 1920s, having met in Swarowskys sister Gina Kauss's literary salons.
Mali Pfitzner, the widow of Hans Pfitzner, thanks in this letter Swarowsky having conducted a performance of Palestrina without rehearsal. 'Finally there is someone in Vienna who can conduct Palestrina'.
Mali refers to two performences of the cantata she heard with Keilberth in Munich and how much she enjoys being in Vienna. The last time apparently was together with Swarowsky in the air-raid shelter of the hotel Imperial in May 1945.