A knowledge of music had begun to spread among the people. Not only did the constant hearing of the noble masterpieces of their time tend to cultivate their taste, but they began to practise music themselves. Conservatories had been founded in Venice, Rome, and other cities, and as far back as Willaert's day it was fashionable for young ladies of good family to learn to play the monochord, one of the precursors of the piano. The music written for the instrument was precisely like that for the organ, polyphonic in style and learned in treatment. The study of such music was naturally very difficult for beginners, and it became necessary to supply them with something simpler. The music of the Roman Church was brought into strong contrast with that employed by Luther in his work of the Reformation. Luther insisted on the exercise of individuality in worship. He held, contrary to the Church, that every man had a right to study the Bible for himself. He even gave communion to the laity. In direct line with such work was his revival of congregational singing, which had been generally unpractised since the days of Ambrose. The first Lutheran hymn-book was published in 1524. Luther employed many extant folk songs and caused new tunes like them to be written. He is said to have written "A stronghold sure." These Lutheran hymns were broad and simple chorals, like those of the Protestant Church of to-day. The spread of their use among the Protestant congregations of the time was an attraction toward that form of worship which the authorities of the Roman Church could not ignore, and hence the Catholic composers moved toward a simpler style. The story of what followed the recognition of these influences by the fathers of the Church has been very prettily told, but unfortunately it has been of late discredited. The story is that two parties arose in the Church, one of them demanding the abolition of all the extant church music and a return to the plain chant of Gregory, and the other that the music of the time be preserved, but its style simplified. The Council of Trent (1562) discussed the matter, and in 1563 Pope Pius IX. appointed a commission of eight cardinals to take measures of reform. Cardinals Borromeo and Vitellozzi, appointed as a sub-committee, went to Palestrina, whose music had already attracted attention, and asked him to write a mass demonstrating that the church music of the time could be preserved. He entered upon his task with such enthusiasm that he wrote three masses, of which that called the Marcellus mass was performed with enormous success.