From the LCMS website:
Johann Walter (1496-1570) began service at the age of 21 as a composer and bass singer in the court chapel of Frederick the Wise. In 1524, he published a collection of hymns arranged according to the church year. It was well received and served as the model for numerous subsequent hymnals. In addition to serving for 30 years as kantor (church musician) in the cities of Torgau and Dresden, he also assisted Martin Luther in the preparation of the Deutsche Messe (1526). Walter is remembered as the first Lutheran kantor and composer of church music.