From his third book on counterpoint.
Rule #1 Begin and finish with perfect
consonance. It is, however, not wrong if the singer is improvising a
counterpoint and ends with imperfect consonance, but in that case, the movement should be many-voiced.
Sixth or
octave doubling of the bass is not allowed.
Rule #2 Follow together with tenor up and down in imperfect and perfect consonances of the same kind. (Parallels at the third and sixth are recommended, fifth and octave parallels are forbidden.)
Rule #3 If ténor remains on the same note, you can add both perfect and imperfect consonances.
Rule #4 The counterpointed part should have a melodic closed form even if ténor makes big leaps.
Rule #5 Do not put
cadence on a pitch which would confuse the mode.
Rule #6 It is forbidden to repeat the same melodic turn above a
cantus firmus, especially if the cantus firmus contains that same repetition.
Rule #7 Avoid two or more consecutive cadences of the same pitch even if
cantus firmus allows it.
Rule #8 In all counterpoint, try to achieve manifoldness and variety by altering measure, tempo, and cadences and varying the use syncopes, imitations,
canons, and pauses; sometimes with, sometimes without. But remember that an ordinary chanson uses fewer different styles than a
motet and a motet uses fewer different styles than a
mass. ==Musical Compositions==