La fille du régiment and Boris Godunov, are a what?
La fille du régiment: La fille du régiment ("The Daughter of the Regiment") is an opéra comique in two acts by Gaetano Donizetti, set to a French libretto by Jules-Henri Vernoy de Saint-Georges and Jean-François Bayard. Boris Godunov (opera): Boris Godunov (Russian: Борис Годунов , "Borís Godunóv") is an opera by Modest Mussorgsky (1839–1881).
opera