Two Part Motets
In the Renaissance the Motet was a vocal composition based on a sacred text. The rhythm of the text and natural accents dictated where notes were placed in the music. The liturgy of the church was often used, and the Kyrie, Sanctus, Benedictus, and Agnus Dei are short texts. They were commonly written in a melismatic style, with many notes per syllable. The Gloria and Credo, with many more words, were frequently more syllabic, with one note per syllable. Another technique that composers adopted was repeating short phrases, which provided more words.
Structurally, the phrases in the text became melodic phrases that ended with internal cadences. The style was imitative, and a new phrase after each cadence set up a point of imitation between the voices. A common technique was invertible counterpoint between the voices. This means the two parts can be interchanged, with the upper part becoming the lower part and vice versa. This is usually found with an octave between the parts. Upon inversion the imperfect consonances remain consonances, but when the perfect 5th becomes a perfect 4th, a problematic dissonance may occur.