At first glance, it would be hard to find two musicians more different than Josef Gabriel Rheinberger (1839-1901) and Nadia Boulanger (1887-1979). He was a German Romantic composer who lived in nineteenth-century Munich, rubbing shoulders with Wagner, Strauss, and Hans von Bulow. She was a twentieth century French musician who studied with Faure, but gave up her own compositional aspirations to dedicate her life to teaching. A closer look at their lives and work, however, reveals similarities between these two musicians so different in time and place: both were devout Catholics, both called the organ their principal instrument, and both had a remarkable impact as composition teachers, particularly of American students. An examination of the teaching methods of Rheinberger and Boulanger further demonstrates that, although their musical backgrounds and personal musical aesthetics were very different, their teaching was so similar as to suggest some universal truths about the successful teaching of musical composition.