one of the confessions of Lutheranism, a defense and elaboration of the Augsburg Confession, written by the Reformer Philipp Melanchthon (Melanchthon, Philipp) in 1531. The first version of the Apology was hastily written and presented to Emperor Charles V on Sept. 22, 1530, at the Diet of Augsburg, after the Emperor had declared that the Confutation (Aug. 3, 1530), prepared by Catholic theologians to refute the Augsburg Confession (June 25, 1530), properly presented his Catholic faith. The Emperor demanded that the Reformers return to the Catholic Church, and he refused to accept the Apology when it was presented to him.

After Melanchthon returned to Wittenberg, he obtained a copy of the Confutation and decided that a more complete reply to the arguments of the Catholic theologians was necessary. He rewrote and expanded the Apology to more clearly and completely explain the faith of the Reformers. The Latin edition was completed in April or May and a German translation by Justus Jonas was published in the autumn of 1531. Luther and others soon recognized the Apology as an excellent exposition of the Lutheran faith. It was cited at various meetings and conferences and was finally included in the Book of Concord (1580), a collection of doctrinal standards of Lutheranism.

Seven times longer than the Augsburg Confession, the Apology is considered one of the most brilliant of the Reformation theological works. Melanchthon's broad knowledge of Scripture, theology, history, and linguistics is evident in it. About one-third of the work is concerned with the problem of justification, while other subjects treated include the church, human tradition, the invocation of saints, marriage of priests, the mass, monastic vows, penitence, and original sin.