The changing from one key to another in the course of a section of a comp. by evolutionary mus. means (not just by stopping and starting anew in another key) and as a part of the work's formal organization. The simplest and most natural modulations are to the related keys (or attendant keys) i.e. to the relative minor or major, to the dominant and its relative major or minor and to the subdominant and its relative minor or major. The tonic major and minor are also related keys, modulation from one to the other being simple, but they are not usually so described. Chromatic modulation, found frequently in Wagner, Franck, and Strauss, in general means altering a chord by means of a chromatic change. It can also be achieved by moving basses up or down major or minor 3rds. Enharmonic modulation covers the use of chords altered by enharmonic means, e.g. turning a dominant 7th chord to a Ger. 6th. Modulation becomes less of a feature in atonal mus. because of the enlargement of the scale. First composers to use modulation may have been Obrecht and Desprès. Chromatic modulation occurs in madrigals of Gesualdo and Monteverdi. John Bull's organ fantasia Ut, re, mi, fa, sol, la modulates a whole tone upward successively into different keys. With J. S. Bach, modulation became integral part of fugue.