 From 1986 to 2002, the first period of the merger of the NKO into the NPO Foundation, Hartmut Haenchen was chief conductor of both the NKO and the NedPhO.Philippe Entremont has served as principal guest conductor of the NKO.Yakov Kreizberg succeeded Haenchen as chief conductor of the NKO and NedPhO in 2003, and held the posts until his death in March 2011.