Which intervals were primarily used in Gregorian Chant?

The intervals primarily used in Gregorian Chant are the fourth, fifth, and octave. This style of early music, which forms the backbone of Western liturgical music, is largely monophonic and modal, relying on these specific intervals to create the melodies that are characteristic of the chant.

The perfect fourth and fifth, in particular, are fundamental intervals in Western music and were highly valued for their consonance and stability. The octave is equally important, as it creates a point of reference for the melodic structure, allowing chants to be sung in a range that is comfortable for the human voice.

This focus on these intervals reflects the tonal practices of the time, which emphasized diatonic scales and modal harmony. By using fourths, fifths, and octaves, Gregorian Chant laid the groundwork for later polyphonic developments and harmonic systems that emerged in subsequent musical eras.