Composing for the stage after the Second World War saw experimentation and an opening up to previously unheard of fields such as happenings and performances. This vanguard in opera was only timidly in evidence in Spain as a result of the fragility of cultural structures during the dictatorship. The relative openness of the 1960s prompted the appearance of groups such as Zaj and Musica Oberta, which promoted an experimental avant-garde theatre, whilst the subsequent reconstruction of cultural institutions would enable the works of composers such as Leonardo Balada, Luis de Pablo, Jorge Fernández Guerra, Tomás Marco and José María Sánchez-Verdú to be included in the programming of major theatres.