The Portland Symphony orchestra was reorganized in 1947 as a permanent professional group. Werner Janssen was engaged for two seasons as principal conductor, from 1947 to 1949, followed by James Sample (1949–1953). Guest conductors were engaged for the 1953-1955 seasons (in lieu of a principal conductor), including Carlos Chávez, Enrique Jordá, Dimitri Mitropoulos Thomas Schippers, Boris Sirpo, Russell Stanger, and Igor Stravinsky. Theodore Bloomfield was one of these guest conductors, and he also became the next regular conductor (1955–1959). The Italian conductor Piero Bellugi (1959–1961) became only the second non-American principal conductor since Hoogstraten. Each of these early principal conductors in the reorganized symphony era left after only a few years because the orchestra lacked financial backing. Bellugi also refused to return for a scheduled guest conductor engagement in the spring of 1962, citing the programs lacked sufficient scope for his talents.