Definite ideas of harmony were beginning to take root about this time. Ramis de Pareja, the Spanish theoretician, in 1482 had, by his new mathematical definitions of the ratio of intervals, established the consonant nature of the triad; Franchino Gafori and Ludovico Fogliano (d. 1539) had insisted upon the same principle. In 1558 Gioseffo Zarlino[107] gave to the world his _Institutioni harmoniche_, which, following the Ptolomean determination of intervals, established the natural relations of the tones of the major triad (_divisione armonica_) and in the course of the century his ideas of harmony became the common property of musicians. With harmony as the predominating principle of music, with 'vertical’ hearing rather than 'horizontal’ as the prevailing habit, and the constantly freer use of chromatics, the doom of ecclesiastical modes was sounded, even if not fully accomplished till later, and the real advent of modern music had been reached. The Italians, from early times as to-day primarily and essentially melodists, never found great appeal in the barbarous descant and counterpoint of the Netherlanders. 'But they could not but perceive the charm of harmony, once it had been cleansed of its dross, when composers no longer worked for the eye of their expert colleagues alone, but for the ears of the people as well.’ Hence polyphonic music was gradually accepted in the place of the native monodies which had now lost caste, and it became fashionable to perform motets for the entertainment of one’s guests. However, the number of native singers able to perform this 'learned’ music was insufficient to supply even the churches outside of Rome, much less the palaces of the aristocracy, until the increased influx of Netherlanders as singers and teachers spread their art among the musicians of Italy. During the sixteenth century the simplification of notation made the art of reading music accessible to the _dilettanti_, who now formed musical coteries for the performance of polyphonic songs. Native composers busied themselves to supply the demand and their products were spread broadcast by enterprising publishers, for meantime, in 1476, the art of printing had been introduced in Rome.[108] The first of these publishers was Ottaviano dei Petrucci, who, though not its inventor, so advanced the art of music printing as to render it a practical medium. His office in Venice produced in 1501 a collection of ninety-six songs written by various composers. Thus he brought polyphonic music to the people and so caused the old monodies of the lutenists and earlier masters to pass still farther into oblivion.