Pope Pius IV., having made thorough investigation, came to the conclusion that the style of music generally cultivated was open to serious objections. It was in 1564 that he convened a commission of cardinals to consider the evil and to prescribe a remedy. This commission was inclined to banish from the church all music except unisons and unaccompanied plain chant; but it was decided, before issuing such a far-reaching decree, to canvass the possibilities of introducing "modern" music which should be free from frivolity. After much deliberation, they commissioned Palestrina to write a mass in the purest attainable church style. The result of their bidding was the composition of the Missa Papæ Marcelli. The success of this remarkable work far exceeded the high expectations that it had aroused. The Pope himself was present at the first performance in the Sistine Chapel, June 19, 1565. So moved was he by the work that, on leaving the church, he exclaimed: "This certainly must have been the harmony of the New Song which the apostle John heard sung in the heavenly Jerusalem, and of which this other John (Palestrina) has given us a foretaste in the Jerusalem on earth." And so it was formally determined that this mass should stand as a model for all church music thereafter to be composed. [Illustration: GUIDONIAN HAND.] This composition by Palestrina, as well as very many others, not only displays a complete mastery of counterpoint and vocal style, but also deep religious feeling and a rare ability in writing for the human voice. The sterling value of his works cannot be overestimated. Their influence upon later periods has been immeasurable. Indeed, we may say without exaggeration, that never in art has such a mighty change taken place as that caused by the immortal Palestrina's reformatory efforts. The earlier contrapuntists collected, stone by stone, the materials which served their successors as foundations for further work. Ockeghem was the first to use these fragments in a symmetrical way and to bequeath a systematic style of music-writing to his followers. Among these was Josquin des Près, who attempted to vivify and to infuse blood into the hitherto lifeless counterpoint. But although his success was considerable, it was reserved for Palestrina to free his art from fetters, and to bestow upon it, as far as was possible, individuality. The most noteworthy of Palestrina's Roman contemporaries were Vittoria, Giovanni Maria and Bernar Nannini, Felice and Francesco Anerio, and the famous composer of madrigals Luca Marenzio. But other cities of Italy had also their schools, all, however, more or less under the influence of Palestrina. The most prominent was the Venetian school, founded by Adrian Willaert.