The Musica duorum of the composer Eustachio Romano, also known as Eustachius de Macionibus, was issued in Rome in 1521. Eustachio, who was a nobleman as well as a composer, dedicated this volume to the future Pope Julius III, offering these small chamber works to refresh the prelate's spirits when he tired of weightier studies. These light, playful duos were collected in the first publication ever devoted entirely to music for instrumental ensemble.