His Vocation As Reformer, Churchman, and Theologian
Chemnitz moved back to Wittenberg in 1553 as a guest of Melanchthon. In January 1554 he joined the Wittenberg University faculty. He lectured on Melanchthon's Loci Communes, from which lectures he compiled his own Loci Theologici, a system of theology. He was ordained to the ministry on November 25, 1554 by Johannes Bugenhagen, and became co-adjutor of Joachim Mörlin, who was ecclesiastical superintendent for the duchy of Brunswick-Wolfenbüttel. When Mörlin resigned in 1567, Chemnitz became his successor; he held the post for the rest of his life.
Through his leadership, Brunswick-Wolfenbüttel was brought firmly into Lutheranism. There he helped his prince, Duke Julius of Brunswick-Wolfenbüttel, establish the University of Helmstedt (1575–76). With Jakob Andreae, David Chytraeus, Nicholas Selnecker, Andrew Musculus and others, Chemnitz took part in a centrist movement that brought agreement among German Lutherans in the writing and publication of the Formula of Concord (1577), of which Chemnitz is one of the primary authors. He was instrumental in the publication of the definitive Book of Concord in 1580, the doctrinal standard of the Lutheran Church. Other major works are Examen Concilii Tridentini and De Duabis Naturis in Christo . These works demonstrate Martin Chemnitz's abilities as a biblical, doctrinal and historical theologian in the orthodox Lutheran tradition. He died in Braunschweig.