Oslo being the first Opera House in the world to let people walk on the roof of the building. The foyer and the roof are also used for concerts as well as the three stages. Most great Norwegian authors have lived in Oslo for some period in their life. For instance, Nobel Prize-winning author Sigrid Undset grew up in Oslo, and described her life there in the autobiographical novel "Elleve år" (1934; translated as "The longest years"; New York 1971). The playwright Henrik Ibsen is probably the most famous Norwegian author. Ibsen wrote plays such as "Hedda Gabler", "Peer Gynt", "A
Peer Gynt (Grieg) ""Peer Gynt" progresses slowly," he wrote to a friend in August 1874, “and there is no possibility of having it finished by autumn. It is a terribly unmanageable subject.” "The more he saturated his mind with the powerful poem, the more clearly he saw that he was the right man for a work of such witchery and so permeated with the Norwegian spirit," his wife wrote of him and his music. Even though the première was a "triumphant success", it prompted Grieg to complain bitterly that the Swedish management of the theatre had given him specifications as to the duration