Tonus Peregrinus provides an overview of the Notre-Dame organum repertoire here, one of the early appearances of two-, three- and four-voiced music in the West. Organum is word music - syllables are held for long periods of time in one voice, while another embellishes it. The result is intense immersion, often for minutes at a time, in a single word or syllable. The minimalist Steve Reich claimed Pérotin as an inspiration in the early part of his career, the late 1960’s. While it’s hard to imagine these medieval composers on the same spiritual and aesthetic quests as those performing in downtown lofts in the ‘70s, the parallel is hard to deny.