 The modal aspect of Dressler's musical poetics agrees in principle with that of Pietro Pontio and other contemporary theorists, but Dressler takes it a step further by teaching the use of the principal cadences of the given musical mode (cadences to the final and dominant degrees) to assert stability in the exordium and the finis, and cadences to other degree during the medio to provide contrast and interest.Dressler's treatise also includes a brief but perceptive sketch in which he identifies four phases in the history of Renaissance music