Question: The American Opera Society (AOS) was a which city based musical organization, that presented concert and semi-staged performances of operas between 1951 and 1970, the AOS also presented many operas to the American public for the first time, including the United States premieres of "Billy Budd", by Edward Benjamin Britten, an English composer, conductor and pianist, and a central figure of 20th-century British classical music?
Sentence (from "Benjamin Britten"): He was a central figure of 20th-century British classical music, with a range of works including opera, other vocal music, orchestral and chamber pieces.
Relevant evidence: No