Harrison Birtwistle's musico-dramatic works all show a preoccupation with intricate formal design. Thus they fall firmly in the Modernist tradition, inherited on the one hand from the Second Viennese School (consider Webern's Piano Variations Op. 27 with its mirrors upon mirrors) and on the other from Stravinsky's later ballets (Birtwistle has acknowledged Agon as a major debt). But in works such as Punch and Judy, Yan Tan Tethera and The Mask of Orpheus, the self-conscious elevation of formal structure (sometimes to its extreme, ritual) distances us, even more than in neo-Classical Stravinsky, from any tendency to realism in the drama. In The Mask of Orpheus, Birtwistle's priorities are clear: he has said repeatedly that this opera is not about Orpheus; it is about writing a particular kind of work with a particular set of problems to solve. He could have just as easily chosen Faust for his libretto (and almost did). With Gawain, however, he seems to be moving in a new direction. Wagner's spirit (particularly as expressed in Parsifal) has entered the work; a new emphasis on drama in its naturalistic sense, and a new relationship between linear, narrative flow and closed forms has transported Gawain to new territory.