Hans Vonk (18 June 1942 – 29 August 2004) was a Dutch conductor. Early and middle years Vonk was born in Amsterdam, the son of Franciscus Cornelis and Wilhelmina Vonk. His father was a violinist in the Concertgebouw Orchestra, and died when Vonk was age three. Vonk studied piano with Jaap Spaanderman at the Amsterdam Conservatory and law at Amsterdam University. During this time, he made a living from gigs as a jazz pianist. He later studied conducting with Hermann Scherchen and Franco Ferrara. Vonk debuted as a conductor with the Netherlands National Ballet. He later married the ballerina, Jessie Folkerts. He also served as assistant conductor with the Concertgebouw Orchestra, and associate conductor with the Royal Philharmonic Orchestra, London. Vonk held chief conductor positions with De Nederlandse Opera (1976-1985), the Residentie Orkest (1980–1991) and the Netherlands Radio Philharmonic Orchestra. From 1985 to 1990, he was principal conductor of both the Staatskapelle Dresden and the Semper Oper, Dresden. In 1988 he conducted at La Scala in Milan in a revival of Jommelli's Fetonte, but then had to take a year off from conducting after being diagnosed with Guillain–Barré syndrome, a neurological condition. He appeared to recover and resumed conducting. He became chief conductor of the WDR Symphony Orchestra, Cologne in 1991. With the SLSO In the US, he made his first guest appearance with the Saint Louis Symphony Orchestra (SLSO) in 1992. In January 1995, he was appointed the SLSO's music director, after Leonard Slatkin, and took up the position in 1996. In 2001, Vonk began to experience muscular weakness, which was not diagnosed to a specific ailment at the time. In 2002, he resigned his position in St. Louis because of these health problems, which were later diagnosed as amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's Disease. His last performance with the SLSO was of Mahler's Symphony No. 4, on Saturday, 4 May 2002. The applause lasted four minutes and was followed by a commendation read by the chairman of the Board of Trustees, Virginia Weldon: "In recognition of his vital leadership and exemplary artistry, as well as his lasting contribution to the rich cultural legacy of both this orchestra and the region of Saint Louis, it is with great pride and affection that the Board of Trustees of the Saint Louis Symphony Orchestra bestows this commendation on Maestro Hans Vonk, on this day, Saturday, 4 May