Robert Hughes composed Intervals while studying with the Italian composer Luigi Dallapiccola in Florence, Italy in 1960. He later organized a tribute to his mentor the year following his death in 1975. Intervals was composed for two voices and two clarinets for the program.

Writing about the concert at the San Francisco Museum of Modern Art on May 13, 1976, Robert Commanday wrote of this work: the Hughes pieceswere lovely and appropriate because they came close to the character of the masters work in spirit, and were of high quality. One was Intervals for two voices ([Anna Carol]Dudley and [Thomas] Buckner and two clarie]nets, to Shelley and Blake, with a fine, close impinging counterpoint.”