Hermann Abendroth
Jānis Kalniņš was the son of composer Alfrēds Kalniņš. He was a student first of Jāzeps Vītols at the Latvian Academy of Music, then with Erich Kleiber, Hermann Abendroth and Leo Blech. His two major operas were "Hamlets" (1936) and "Ugunī" (1937). He was chief conductor of the Latvian National Opera 1933–1944.