The Schillertage selects a group of productions for the Mannheim festival presented both on the theatre 's mainstage ( plus an experimental series of plays elsewhere ) .
The Schillertage is the biannual festival of Schiller 's plays that has existed since 1979 .
The Schillertage , the biannual festival of Schiller 's plays that has existed since 1979 , selects a group of productions for the Mannheim festival presented both on the theatre 's mainstage ( plus an experimental series of plays elsewhere ) .