 The first of these tendencies is also embodied in the work of Gioseffo Zarlino (1517–1590). A towering figure in Western music theory, Zarlino is normally considered as the theorist who initiated the move away from medieval modality and toward tonal harmony. According to Zarlino, rules of composition are good insofar as they produce beautiful music, whose purpose is to “improve” and “delight” (Zarlino 1558: book III, 71). However, Zarlino does not reject the role of rationality, and especially of mathematics, because its laws ultimately underlie the senses of sight and hearing (Zarlino 1588: 34–36).