found: Sessions, R. Montezuma [SR] 2000:container (Opera Company of Boston)
found: Oxford music online, Mar. 6, 2020(On 11 April 1958, under her leadership, the Boston Opera Group (later the Opera Company of Boston) was incorporated. Caldwell conducted and staged the company's productions for 31 seasons, beginning with Jacques Offenbach's Le Voyage dans la Lune in the 1958 pre-season opener through the world premiere of Robert DiDomenica's The Balcony in 1990)
found: Wikipedia, Mar. 6, 2020(The Opera Company of Boston was an American opera company located in Boston, Massachusetts, that was active from the late 1950s through the 1980s. The company was founded by American conductor Sarah Caldwell in 1958 under the name Boston Opera Group. At one time, the touring arm of the company was called Opera New England. Caldwell served as both director and conductor for most of the company's productions throughout its more than three decade-long history. In 1990, after 32 seasons, the company was forced to close due to financial difficulties.)