Hermann Abendroth
De Ridder was born in Dordrecht, Netherlands, as the son of Eudia Lina Pierson and Willem de Ridder, banker, cellist and president of the Dordrecht Music Society. From 1899 he studied violin in The Hague with Carl Bayer, and between 1903 and 1909 he studied violin and conducting at the Cologne University of Music under Fritz Steinbach and Hermann Abendroth. His conducting career started in Arnhem. Here Willem Mengelberg saw him and was so impressed that he invited him to be guest conductor with his Concertgebouw Orchestra in Amsterdam. He later conducted the Residentie Orchestra in The Hague, where he took composition lessons from Johan Wagenaar. He was conductor of the Netherlands National Opera ("Nederlandsche Opera") from 1917 to 1919. In April 1918 in Amsterdam, he married Pauline E.E. Mendelssohn-Bartholdy (grand-niece of the famous composer), whom he had met in Cologne.