In 1541 he was appointed professor of Latin grammar at Wittenberg, and in 1557 professor of the Old Testament. His range of learning was wide, and he published a handbook of Jewish history, a historical calendar intended to supersede the Roman Saints' Calendar, and a revision of the Latin Old Testament.
In the theological conflict of the time he played a large part, doing what he could to mediate between the extremists. From 1559 to the close of his life he was superintendent general of the electorate of Saxony. He attained some fame as a hymn writer, his best-known composition being Wenn wir in höchsten Nothen sein. He died at Wittenberg on the 10th of December 1569. Johann Sebastian Bach composed in 1725 a chorale cantata on his hymn in eight stanzas, Herr Jesu Christ, wahr' Mensch und Gott, BWV 127.