Palestrina composed over 100 settings of the mass (in Richard Wagner's words, with "indescribable depth of expression"), including the Missa Papae Marcelli, composed after an edict by Pope Marcellus that the vocal music for the mass "must be sung in a fitting manner, with properly modulated voices, so that everything may be heard and understood." Palestrina succeeded in doing this with remarkable clarity of line, beauty of modal harmony, and a festive rhythmic sense. The Assumpta est Maria is probably his best mass, with the voices moving more like orchestra parts than block harmony or contrapuntal choirs. ~ Blue Gene Tyranny