 When, however, he reached the beginning of Scene 1, he found that the remainder of the opera required too much revision and elaboration to allow him to develop a full score without first making a second complete draft.He therefore abandoned the full score in ink and proceeded to develop instead an instrumentation draft in pencil, in which he worked out most of the vocal and orchestral details of the four remaining scenes.This "Instrumentationsskizze", as Wagner himself styled it, was completed by 28 May 1854.