Knoxville Iron Company was created in 1868.
Berkshire Opera Company was created in 1962.
Philadelphia Opera Company was created in 1938.
Century Opera Company was created in 1913.
Opera Company of Boston was created in 1958.
Beecham Opera Company was created in 1915.
Lancaster Opera Company was created in 1951.
Manhattan Opera Company was created in 1906.
Early Opera Company was created in 1994.
Opera Company of Philadelphia was created in 1975.
Aborn Opera Company was created in 1895.
Canadian Opera Company was created in 1950.