Glass continued his work with a series of instrumental works, called "Another Look at Harmony" (1975–1977). For Glass this series demonstrated a new start, hence the title: "What I was looking for was a way of combining harmonic progression with the rhythmic structure I had been developing, to produce a new overall structure. ... I'd taken everything out with my early works and it was now time to decide just what I wanted to put in—a process that would occupy me for several years to come." Parts 1 and 2 of "Another Look at Harmony" were included in a collaboration with Robert Wilson, a piece of musical theater later designated by Glass as the first opera of his portrait opera trilogy: "Einstein on the Beach". Composed in spring to fall of 1975 in close collaboration with Wilson, Glass's first opera was first premiered in summer 1976 at the Festival d'Avignon, and in November of the same year to a mixed and partly enthusiastic reaction from the audience at the Metropolitan Opera in New York City. Scored for the Philip Glass Ensemble, solo violin, chorus, and featuring actors (reciting texts by Christopher Knowles, Lucinda Childs and Samuel M. Johnson), Glass's and Wilson's essentially plotless opera was conceived as a "metaphorical look at Albert Einstein: scientist, humanist, amateur musician—and the man whose theories ... led to the splitting of the atom", evoking nuclear holocaust in the climactic scene, as critic Tim Page pointed out. As with "Another Look at Harmony", ""Einstein" added a new functional harmony that set it apart from the early conceptual works". Composer Tom Johnson came to the same conclusion, comparing the solo violin music to Johann Sebastian Bach, and the "organ figures ... to those Alberti basses Mozart loved so much". The piece was praised by "The Washington Post" as "one of the seminal artworks of the century".