 Some were written for four to five voices, with the "bassus" taking the Latin part.Generally, the French text was either a commentary on the Latin text or had some symbolic relation to it.The lowest voice served as a cantus firmus, and usually sang in long notes, with phrases separated by long rests, while the upper voices, singing more quickly, followed the rigid formal structure of the contemporary "formes fixes", particularly the rondeau and the bergerette.