The Philip Glass Ensemble is an American musical group founded by composer Philip Glass in 1968 to serve as a performance outlet for his experimental minimalist music. The ensemble continues to perform and record to this day, under the musical direction of keyboardist Michael Riesman. After Glass wrote his first opera, Einstein on the Beach, for the ensemble in 1976, he began to compose for other instrumentation more frequently, but he still retains the core ensemble instrumentation.