In this thesis, the incidental music in general and the analysis of the incidental music for the play The hour we knew nothing of each other in the production of Viktor Bodó at the Schauspielhaus Graz in 2009 in particular is examined.After a disambiguation and a short historical overview, the development of the dramas text, the premiere and other national and international performances are considered. The incidental music of the dramatic production - composed by Klaus von Heydenaber - and the sounds in the play - done by Gábor Keresztes - are examined in terms of their usage and their musical function in the drama. The incidential music used in this play is compared with the dramatic text by Peter Handke to show similarities and differences between text and staging. In addition, an attempt is made to set the occurring film music quotations with the respective films in reference. As part of the research interviews with the director, the composer and the stage manager of the production were made and the results were incorporated in the thesis. Finally, the production of the audio CD, which was produced due to the great success of the play, is considered critical.