Iwan Otto Armand Knorr was a German composer and teacher of music. A native of Mewe, he attended the Leipzig Conservatory where he studied with Ignaz Moscheles, Ernst Friedrich Richter and Carl Reinecke. In 1874 he became a teacher and in 1878 director of music theory instruction at the Imperial Kharkiv Conservatory, in what is now Ukraine. In 1883 he settled in Frankfurt, where he joined the faculty of the Hoch Conservatory; in 1908 he became director of the school. As a teacher he exerted great influence; among his pupils were Bernhard Sekles, Ernest Bloch, Vladimir Sokalskyi, Ernst Toch and Hans Pfitzner, as well as the English-speaking composers and friends that become known as the Frankfurt Group: Balfour Gardiner, Percy Grainger, Norman O'Neill, Roger Quilter and Cyril Scott.