Ensemble Organum, from France, is one of the most durable groups in Europe, specializing in the music of the early medieval period. With a repertory stretching back to the sixth century CE, the ensemble attempts in-depth re-creations of unusual early repertories, buttressing their performances with musicological research. Ensemble Organum was founded by Marcel Pérès, a choral director, musicologist, and composer. The repertory of Ensemble Organum focuses mostly on sacred music of the Middle Ages, notably including the non-Gregorian chant repertories that otherwise have been little recorded. It's 1997 recording of Machaut's Messe de Notre Dame was widely praised. In 2021 the group issued the album In Memoria Eterna: A Spiritual Vigil for the New Century.