Willem Mengelberg
Kes served as the orchestra's chief conductor from its 1888 founding to 1895. In 1895, Willem Mengelberg became chief conductor and remained in this position for fifty years, an unusually long tenure for a music director. He is generally regarded as having brought the orchestra to a level of major international significance, with a particular championing of such then-contemporary composers as Gustav Mahler and Richard Strauss.