The fourthteenth century saw tremendous development in music. All across Europe, composers were trying to find new ways to push the boundaries of music. This led to the creation of a rhythmic device known as isorhythm. Isorhythm can be defined as a repetition in a voice which contains the same rhythms. The leading composer during this period of time was Guillaume de Machaut, who composed works for many different genres. His motet Felix virgo / Inviolata / Ad Te Suspiramus is a perfect example of isorhythm.
Isorhythmic motets were longer and more complex than their predecessors. Felix virgo / Inviolata / Ad Te Suspiramus is a motet that contains four voices: motetus, triplum, tenor, contratenor.