Apology of the Augsburg Confession

The Apology of the Augsburg Confession (German: Apologie des Augsburger Bekenntnisses) was written by Philipp Melanchthon during and after the 1530 Diet of Augsburg as a response to the Pontifical Confutation of the Augsburg Confession, Charles V's commissioned official Roman Catholic response to the Lutheran Augsburg Confession of 25 June 1530. It was intended to be a defense of the Augsburg Confession and a refutation of the Confutation.

Source: Wikipedia — Apology of the Augsburg Confession (CC BY-SA 4.0)