Dutch conductor (1871–1951) highly regarded for his interpretations of Bach and the late Romantic repertoire. The extent of his cooperation with the Nazi regime during World War II remains a topic of much controversy and discussion. AMQS, signed W. Mengelberg,” on an off-white 3.25 x 2.25 card. Mengelberg pens one bar labeled “Joh. Seb.,” most likely from a work by Johann Sebastian Bach. In fine condition. RR Auction COA.