Martin Luther not only exerted a powerful influence on religious and cultural life in the 16th Century. Luther also revolutionized music (then dominated by the Church) in his time. Essentially, the modern Christian hymn was created by Luther with the assistance of coworkers in order to bring the message of the Scriptures home to congregations. Luther was an ardent music lover who played the lute, flute, and sang with an accurate if not very powerful tenor voice. After his challenge to Pope Leo (" 95 Theses"), during his enforced hiding in the Wartburg Castle, Luther completed his German vernacular translation of the New Testament in 1521. He returned to Wittenberg, overseeing mass publication of this work (the Old Testament was completed in succeeding years). By 1523 Luther had translated parts of the Latin Mass into German ("Deudsche Messe"). He also composed melodies and limited harmonizations for these German translations, but recognized that these could not have the same effect as new works conceived in German (he referred to his efforts as somewhat mechanical, "as though done by apes", a typical bit of self-ironic humor). Therefore, he composed new hymn texts, providing about half with melodies (the exact number is still controversial). He brought in a skilled professional musician, Johann Walter, to harmonize them and urged his friends to compose new hymns. The first congregational hymn book, "Geystliche Gesangkbuchlein", was already brought out in a mass printing in 1524. This hymn book was commissioned by Luther in four-part harmony "in order to give the young men something in place of their drinking and fleshly songs". In other words, from now on, the congregation members themselves were to participate musically in the church service; young would-be pastors were not accepted for training before they could demonstrate musical competence. Just as the mass publications of the Bible for individual study brought about expansion of literacy in the Reformation areas (which at first included France, Netherlands, Poland and Hungary, besides Scandinavia) , so did the mass distribution of hymnbooks foster musical literacy among all strata of society. Congregational part singing retained its hold even in areas that were subsequently won back to the Roman Catholic Church, such as Bavaria. Luther exerted other powerful musical influences: opening up the use of instruments, as well as melodies of all origins in church music, and careful matching of music to simple and understandable texts (instead of the polyphonic music and often interwoven Latin texts previously characteristic of the church services.) Thus was born the relatively short and pungent thematic construction of German music, in contrast with the longer more cantabile Italian lines, and the complex Russian melodic structures. Luther remained musically active to the end. One year before he died Luther supervised and wrote the introduction to Johann Walter's hymnbook of 1545.